Here are some of my thoughts about 3 stages of the game based on my full playthrough.
1. I’ll start with the endgame. Endgame is what I like about Galciv 4 very much. As a long time Stellaris player (so forgive me, if I compare the two games), I can say that it was its weakest part of the game due to progressive lag and lack of meaningful ways to end the game (barring time limit and total conquest). And Galciv 4 handles endgame very nicely, giving a player several ways to win, from easiest and fastest (prestige) to the most tedious (conquest and diplomatic) plus providing some additional tools to play with – challenges. Of course it can be made even better. For instance, more interesting challenges can be added and something akin to endgame crisis could emerge making every race to fight for their survival and join forces. But overall, it is in a good spot now.
2. Early game is traditionally a strong stage of the game for 4x games because there is a thrill of discovery, expansion, early contacts etc. Galciv 4 in general does well here too. However what it (and all other stages of the game in fact) could benefit from is, first, diversifying points of interests and, second, adding chains of events with substantial rewards at the end of the chain. Right now, flag ships do not interact with planets, only with space objects (artifacts, capsules etc.) which is weird given that planets are huge and are bound to have many interesting things waiting to be discovered (ancient ruins, forgotten alien cities, anomalies etc.). Chains of events with potentially substantial rewards on the other hand are a great way to keep players intrigued and engaged in exploration in the early\mid game and something, Stellaris for example, handles very well. Overall, the early game is decent\good, but can be made even better.
3. Now to the midgame. Currently it is the most problematic part of the game for several reasons, in my opinion. First and foremost is that midgame is supposed to be all about diplomacy, political landscape and wars. During my playthrough (against 10 genius AI’s) I’ve noticed that in the middle of the game there were almost no wars in the galaxy and diplomatic interactions were limited to trading. The AI need to be more assertive, especially when their worlds are subject to alien influence and overtake. Diplomatic tools (alliances, agreements etc.) need to me made available earlier and easier to use, because right now, you need 9 points in relations with a given civ to propose an alliance, which is quite hard to achieve, especially given that most\all diplomatic bonus modifiers don’t seemingly work. Alliances and coalitions can make the midgame so much more interesting and unpredictable, but as of now, they are a thing for a very late game, when they don’t matter much if at all. Another thing, midgame (and other stages as well) could benefit from is making leaders more meaningful. I like that leaders have different stats and traits, but most of these traits are not impactful enough imo. In addition, loyalty could also be made a more interesting mechanic than it is now. Making leaders more valuable and impactful is one of the ways to make midgame more interesting. Overall, midgame is not in a very good state right now and could use some love, I think.