Well, the problem with the end game are not the victory conditions that, yes, they needed to be better, but so many other things like the snowballing. They introduced age transitions to stop snowballing and THEN made bonuses like in no other Civ game where, by the beggining of the modern age you could have the equivalent of a worldwide conquest yields (on other Civ games) on a confined little empire of 7-10 cities. And many times the colonial wars of the exploration age left you with a navy that would shame the brittish one, that you can throw to your long time beef with him or her having little to do with its land units against the starting naval class (much less if you upgrade). Something worsened by the existence of navigable rivers. And so on, and so on...
Look, I love this game, I've spend about 500 hours in it, but I despise this community. Their inmovilism didn't let the devs explore the concepts introduced in the unfinished and cheap cash grab that was the initial release. Which was very critizisable, for sure, but their lack of perspective put us in a course correct path where the game barely advances and just pivots to previous entries.
Edit: also no mention of an "undo" button for a whole year is uttery BS.