I'm obviously somewhat new at this, and it's not meant to be a whine thread, but let's look at it from a logical perspective:
Light Frigs counter - Flak Frigs, Siege Frigs, Carrier Cruiser, Support Cruisers, and Disable/Repair Cruisers. You just countered 5 different ships by building the most basic ship in the game, which everyone has access too naturally.
Long-Range Frigs counter - Light Frigs. 1 thing. Are you kidding me? Even if Vasari's LRF's were superior early game, which we know that they're not, it still wouldn't make up for this huge deficit in role that they have compared to Light Frigs. Granted, for Vasari they can be made a lot more effective than a typical LRF because of the phase upgrades, aoe upgrades, and synergy with Subverters, but early game this hardly matters, as most of this stuff is a mid-late game advantage. Even if you mass LRFs early game (which is pretty much your only option with Vasari besides SB rush), an opponent, especially Advent, can simply counter you with mass scouts and shut you down. Since their LFs are also so good, pretty much whatever you build can then be countered, especially since LF's naturally counter so many things.
This is just one example, but TEC can do it as well, maybe just not as effectively.
A lot of people have been bringing up: "But many pro players use Vasari, so they must be good." Just because pro players use a race, does not make it balanced, and using that as an example is a logical fallacy. Pro players may use Vasari for several reasons. One, they are a challenge, because they have a disadvantage over other races early on. Two, they are the most fun to play (in my opinion), and have great early resource bonuses that only TEC can try to match (in their research tree and with their Scouts). Thirdly, late game in the hands of a skilled player they can easily become the best, if for no other reason than upgraded LRF with Subverter spam, or even just bomber spam and of course Phase Stabilizers.
As absurd as this all may sound, I bring it up because of another RTS game I used to play when I was younger called Total Annihilation. There were 2 races, and one race, Arm, was superior in every way early game (and for the most part late game) over the other race, Core. However, pro players would always use Core because it made them feel better when they won.
Back on topic, the point is: Light Frigates are, in my opinion, the best, cheapest, and most versatile unit in the game, which can be built from square one. Giving one race a huge disadvantage in this aspect is only asking for trouble as far as balanced is concerned, and therefore it should not surprise you that I've switched races from Vasari to Advent, because their Light Frigates are so much better.