I think that on its face, it's a great idea. Starbases don't quite work the same now that phase lanes shift. Two problems however, its implementation and the fact that the Vasari starbase needs to be actually mobile compared to the others.
Perhaps a component that enables the starbase to stay in a fixed position relative to the sun (so rotating fairly slowly). But then it could run into other buildings in the well... Something to think about definitely, and hopefully others have (better) ideas as well.

You can run into a lot of issues with stuff like this. There would be a lot of complex code built into getting a component like that working, and it would immediately become so important that players would be saying it should be a standard feature in the game, not something they have to waste a slot on. There's also a lot of wacky use cases it would have to handle as well. Simplest solution would be to have an engine component for the starbase that allows it to move very slowly.

Part of the Vasari's appeal is that the Starbase moves, so you're taking something special away from them by doing that though.

I think the vasari starbase acting like an TITAN trapped in a gravity well is always going to be a huge advantage over simply being able to slowly move a TEC stabase from one point to another once every 15 minutes (takes an additional 5 mins to orbit a planet minimum, which would be the maximum you would allow it's small retro thrusters to move it each recharge). For one once in motion you cannot change the burn and so cannot react like a vasari stabase can. You cannot give more than one order every 15 mins to the TEC starbase. Perhaps additionally it should cost money to move it in addition to the money spent researching "retro thruster burn" for the TEC starbase? It would basically be like building a new TEC starbase except this time you are moving an existing one.
I don't see it as a threat to the Vasari starbase's advantage.

I prefer the current arrangement where the structures aren't inherently moveable. If they do wind up orbiting the planet I'd prefer they do so in such a way that the players can't control them.

Players who don't like the moving phase lanes do already have the option to turn off orbits (giving them the static maps and always-perfect structure placements that they want). Giving all structures the ability to move would detract from what I've seen so far. Outside of the Vasari, who are orbital rulers by lore, I'd prefer to keep all structure positions static as the gravity well travels along its orbit. That said, I'd prefer that the Vasari are the only faction with the ability to move it's structures.

Now from a modding perspective, I do want to be able to set things up so that a custom faction's structures all have a default move speed of "0" but with an ability that, while active, provides an additive move speed buff which gets applied to the structure - giving it the ability to reposition (assuming the destination is within range). I do want to iterate though that is is a capability I want to use for a modded faction, not for any of the default-game factions.

Isn't one solution to the challenge you're describing to patch those "holes" via Garrisons & strikecraft? I've been using them to snipe siege vessels so that the planet won't fall immediately (if my fleet is too far away). Usually if I have issues it's because I've over-extended myself.

For the TEC specifically, would bringing back the Gauss' [Burst Rockets] and/or the [Meson Bolt Cannon] abilities help with buying you time to get a fleet to defend? Or the stand-alone planet shield that gave a damage reduction? When it comes to the challenge of moving planets, wouldn't the Advent also share this same 'disadvantage'?

To me, the whole point of the orbit mechanic is to challenge the entrenchment playstyles. Now that they've given the players the ability to see the map state 1 hour in advance, can't we scuttle & then rebuild as needed (assuming we want to keep all structures in a particular area)? If all we're doing is slowly repositioning the structures every couple of minutes, then haven't we essentially negated the new mechanic whilst adding on more 'work' for players? If we're adding actions for player's to take, my own preference is that they are interesting and not just maintenance.

The phase lanes are not consistent either, so the first phaselane you camped with the starbase can't be tracked indefinitely. Another thing to consider is the game setting {orbit speed}.

I might be really misunderstanding you, but the way I'm reading your request it sounds like what you really want is to have a static map (so, no changing phase lanes & planets that are consistently positioned with respect to each other) that still visually spins around the star.

This was solved in sins 1 ages ago. Planetary shield tec just need to be earlier lol

Beric I think that fleets should have a lot of freedom in a gravity well. I don't want to take that away by allowing starbases to cover too much. 

Treveon I am also not keen on every planet having a planetary shield early on. Not because it is not a solution. But because it seems silly from a suspension of disbelief angle that such an advanced tech is standard practise so early on. In addition to that making every battle the same.. i.e. attack the starbase that will be in every planetary gravity well.

Starbases might eventually be in every gravity well but battles should be more dynamic for most of the game. You should have to choose where you put a starbase.

When you do choose where to have your starbase, you should be able to adjust the starbase you put in that very special strategic gravity well so that it does not become useless. A starbase sitting on the wrong side of a gravity well protecting a few cheap buildings instead of a planet is pointless against siege frigates on the other side of the planet. Especially when they are protected by a large fleet.

Against AI what I say above is valid. No idea how a starbase is useful against humans who would just go round them. Against humans starbases would be put near gravity well phase lane entry points to mitigate an attack as it went past to the planet. Then you better hope that you have a fleet nearby or you will lose the planet. 

The solution against players might be planetary weapons that fire up out of the atmosphere as they come past as the planet rotates. These should only be strong enough to kill a few siege frigates.

P.S. Perhaps a new unit called the space tug could be built. You could build the correct number needed to move any building in orbit. Then you could adjust defences slowly but to anywhere. The enemy could pick them off if they were trying to move things while they were attacking.

The new space tug unit in action

That would work. But you would have to be able to build the amount needed to move the mass of a starbase sized object. Which would cause objects in gravity wells to be built too quickly because you would end up with many over the default # of construction frigates. So a new unit might be better. A new unit would also make the player consider the fleet population costs and how to get the tugs to their destination and maintain their numbers if they are killed.

The construction frigates I suppose would have the benefit that if they were destroyed you cannot simply build new ones. You have to wait. But this would feel arbitrary and frustrate the player. 

Quoting Blair Fraser,

reply 17

This is a ongoing discussion internally but we are almost 100% going to make the planetary shield and/or something like aux-gov available much earlier. Not to say we won't make other changes as well. This thread has lots of great feedback and suggestions, thanks!

Very happy to read you guys feel that to do something/add onto the orbital mechanics fits! Not sure whether I like this idea on the face, but it might be the best idea. Interested to see what you guys will implement and I will definitely test it.

I'd suggest a series of changes specific to faction.

The vasari can move their bases. Having the base be able to do an in system warp to engage quickly so fleets can't ignore the station is a great mechanic for defense.

For the Advent, bases should be fighter hives. Failure to engage with it will result in waves of bombers tearing apart your fleet before you can take the planet. Major buffs to fighter capacity is logical along with rapid manufacturing to ensure the gravity well is always full of them.

For the TEC, we need to expand the zones of control. Instead of just making the range of stations have larger range why don't we have satellite defense platforms for loyalists and a station defense fleet for rebels akin to the garrison forces. That way it's flavored to the faction. Tec loyals can have 2 bases already. Each of those bases should have 2 defense modules that are placed in different areas to ensure coverage around a planet. Killing the base itself destroys the platforms (by functionally cutting of their supply's). For rebels the base has its own fleet that can't jump and can be replenished by the base. Similar to fighters of the Advent, but instead of swarming perhaps the station has a mechanic to call for all available support from civilians. ships will appear where you click and could even be animated to swell up from the planet itself for its defense. This allows you to quickly engage the ships bombing the planet.

This enables all stations to protect a planet in a way that is friendly and consistent with the lore and abilities of their respective faction while also accounting for rotating phase lanes.

I strongly support a solution that is flavored to the faction and solves the primary issue which at its core is the ability for fleets to bypass defenses that are otherwise well made. The way I see it it boils down to being able to deny the planet being taken until the starbase is gone. What form that takes can be expanded on.

A fun vasari concept would be phase lane stabilization tech that causes all ships coming to a planet regardless of direction to appear near the base.

Or allow them to completely consume the planet and replace it with a starbase that acts like a planet.

I don't think planetary defenses should be able to take on a main fleet. The goal is to delay them while your fleet jumps to the planet.

In order for that to work, players should not be able to simply bypass defenses. These are advanced space faring races and they are very much so aware that planets orbit so it stands to reason they would design their defenses with shifting phase lines in mind.

It's required for logical consistency within the lore.

Heck now that phase lanes more, there an argument for all defenses structures to be repositionable in addition to star bases.

It's not like these factions would just accept that during half the year their planet is basically defenseless.

From a gameplay mechanic perspective. Players should be on the offensive if they want to attack planets with small fleets. The longer you allow a planet to exist the harder it should be to take. Capitals that have been untouched the whole game should take an entire fleet supply fleet to take them. They have had that long to build up their defenses.

Players should trade outlining colonies back in forth in smaller combats using the whole galaxy as a sort of chess board. Timing their strikes when planets are weak and disrupting industry, or research of their enemies to get the upper hand that will allow them to support larger fleets.

I like the idea of supply lines. It incentivises actually taking planets instead of just bombing them and moving on. Size of fleet should be dependent on robust supply lines. Such that fleet in a fledgling world would not be able to source enough supply's to maintain it and would need to send some back to the more established planets.

Offensive strikes would have time limits on them. Established the beach head and supply lines quickly or be forced to retreat.