You're playing a 4 player-sized strategy map with 2 players. That gives you a lot more freedom to expand wildly and get huge swathes of territory without opposition. Of course you're getting too much money and RP. If you play the 4-player map with 4 players, your income is a lot slower and it gets harder. Like I said, try playing the 4 player map with 4 players.
Look, please stop asking for alliances and trade. As much as you wish it, this game is not a 4X, it was not marketed as a 4X, and it was not designed to have a 4X depth of politics. Those were not removed from the multiplayer, they were never in single-player. *waves hand* This is not the 4X you are looking for. [/ jedi]
I don't agree that gold needs to be gained slower. Try the 4-player map with 4 players and see.
I did try 4 players just so you know and let me tell you, no difference whatsoever, the only difference was, that by the end, the last enemy was seriously weakened by the other neighbouring ai and was much easier to conquer.
the 1st 2nd ai died within the 1st 15-20 turns or so.
After researching armour i spammed in about 10-15 of them and wiped them out, ending the game the same way, just faster.
Note: the screenshot was made for demonstration purposes, and the reason why i only did 1v1 was because it is somewhat balanced compared to 1v1v1v1, since we both have a chance to cap half the map.
in 2v2 it took even less than 25 turns to win, due to a helper, who owned at least 40% of the map by the end.
Also ive never said that things like diplomacy or politics have to be complicated, nor that they had to be at the level of 4x games.
And please take a look at the raven phase in single player, when you make POLITICAL DECISIONS which, by your words, were never in single player.
Also the single player has politics in politics are also trade decisions and such(going by youtube vids), strategy map, and battle, of which the strategy map is turn based. It is 4x or has 4x elements (and not just a few of them). So adding in some stuff that would balance the game better isn't a bad thing.
Also, i don't know what i'd do better, but owning a larger territory makes it so that the enemy has very little chance to win, which could be balanced with different research techs, or political decisions or other stuff, i'm sure the ppl at larian could come up with something.
Of course it's a common thing that the bigger empire wins, im not saying that a small empire should be able to defend, but even 2-3 territories have such impact on incomes, that it gives you an edge over your enemies.