Part of the thing is that I think a lot of players differ on what they want in difficulty. If the optimal difficulty is for AI performance to try to match player performance from the start to the end, ABC will do it best because players DO snowball. If you want AIs to progress at a set rate in a relatively close clump with a few dropping off as they get beaten up, we can probably make that happen better with a scaling % bonus instead of ABC. That makes their performance less responsive to their own actions and the gamestate, and makes them more of a bar saying "You must be this tall to win" instead of feeling like real opponents however. Real players snowball. Real players that are doing good get and maintain a strong lead. Real players that are getting kicked into the dirt are not great at coming back and perform much worse than a player flourishing in a wonderland of great people and wonders. I prefer AIs that mimic that behavior a bit better, within reason. So while I can support some efforts to keep the top-end in line with what a player really going off can do, I don't want to switch to a system that makes the AI so much less dynamic and responsive to the gamestate.