Been away from the game for few months but got back to biz after DA came out.Generally I can join the "horde" that mostly agrees with Wyndstar so let's get started with the stuff I
DISagree with him. Take all of these with a grain of salt as I've only played a handful of games in last 4 months or so.
Starbases: I don't see any reason to make them huge to start with. Instead I'd give them more HP with each added module (military modules might give more HP than others) so that they may end up as huge.
Anomalies: Considering what Anomalies are (mostly some old stuff that's been left there by someone - someone including The Big Bang) I see no reason for them to spawn during the game. In my opinion it would be more logical way to give surveying some value after the start of the game to have Anomalies that couldn't be harvested until later in the game (whether it's for the monster guarding it or a tech required to get the benefits).
Planetary Defense: While changing Planetary Defense to block all but Traditional Invasion would surely make the improvement better it wouldn't make a slightest sense to me. But I do think that there's something rotten in the invasive war at the moment. I'd much rather have AI's to invest more on Soldiering if its neighbours are starting to research invasion techs. Also I'd like to have some sort of costs to have billions of soldiers waiting in space between wars and even the cost of the invasion tactics could be related to the size of the invading army.
Then to the stuff not directly related to "agreeing with Wyndstar" notion.
Tech Trade & Diplomacy: While I consider the current Tech Trading implementation to be the best this far it still has some flaws.
1) AI overvalues techs it is unwilling to trade to the point where it's actually hurting itself. For example I'm allied with a race with a certain Extreme Colonization techs and I'm warring with another race that has a planet or two requiring that tech, and my ally is completely unwilling to trade me those techs no matter how sweet deals I'm offering.
2) I'd like that AI could actually give up a planet during the Peace Treaty. At times I've completely wrecked AI's military, his economy is in ruins but most of his planets are in awkward position for me except that one crappy ball of rock in the middle of my empire. But no, I've never had AI to give up a lonely planet in the middle of a hostile space to save its butt.
3) More of those diplomatic options are needed. Things that are already mentioned like "get your ships off my space" would be great. I might like to have a chance to cancel a treaty with a severe cost at relations. All in all, I'd like to be able to extort other races in more ways
Espionage: Spies are a nice thought but...
1) I should get basic information about the races through diplomatic channels (that is 1st and maybe 2nd level of intelligence). Trade routes should give some small amount of intel, neutral relations and better should also contribute as well as treaties. Low level of intel in the game is so low it just can't require a finesse espionage system to reach.
2) IMO Spies are quite poor because they represent the whole espionage now. They are multipurpose tools that do nothing in cost efficient way. I'd like to separate the spending on spies and generic espionage where the latter would give you more intel about the races while spies would be used in more direct ways like the current nullifying of improvements.
Big vs. Small Ships: I don't think there's any reason why small fighters should be equal to massive capital ships in actual space combat. But read on...
More About Invasions: One thing where smaller ships (tiny and maybe small) could excel is assisting the invasions. According to many sci-fi movies the small fighters are able to fly within the atmosphere so they could give air support to the ground troops. That might be a reason enough to keep some tiny fleets in your arsenal even during the late game. Related to the invasions, I'd also like to have a chance to bomb the planet from the orbit with large+ ships. There could be a "bombardment" module that requires Planetary Bombardment and allows the ship to attack a random improvent on the undefended planet.