Omagawd omagawd omagawd, I finally won on Deity @_@. I'm now technically one of the best players according to 2K, even though Deity is 100% luck based. Now I can start playing on Normal again and just have fun. Ironically, Prince (Normal) is the only difficulty that requires skill. Easier than that, you get bonuses and you need to suck to lose. Harder than that, the CPU gets bonuses and luck becomes more important than skill. The devs idea of making the game harder wasn't to make the AI smarter, it was just to cram so much bonuses down their throats that the game gets ridiculously unbalanced and you can only win through diplomacy on Deity, and maybe Culture on Immortal if you get extremely lucky. I mean geez, on Deity the AI starts with two settlers, two workers, three warriors and a scout. And expect them to be nuking you by the 1500s and building spaceships by the 1600s. Only way to win is lick their asses, give them all your money, bribe them some more to make them fight each other while you stay in the shadows and hope one of them will build the United Nations while you're still struggling to get Steam Power so you can get the City States on your side and somehow get elected President of the World, even though they could annihilate you in one turn.
I've now beat the game with every civilization, every map, every size, every difficulty, every victory conditions, every policy trees, filled the whole tech tree and gotten quite a few civilization-exclusive achievements.