My biggest request for the new version is to simply have a self-sustaining boxing universe that the AI controls. Boxer profiles are randomly generated into the universe and boxers follow a linear career path. The closest thing I can relate to this is the old boxing game TV Sports Boxing (You can play this game freely now in DOSbox or an amiga emulator:
http://www.cinemaware.com/clsgame_tvboxing.asp ). That game had the most developed boxing universe I've ever seen. Unfortunately the fighter profiles were all hard coded so they ran out after a period of time. The other thing related to this is that the game should have a 'date' system in place to show the passage of time and some sort of history.
One of the hardest things to achieve in a universe like this is how to pad a fighter's record. You really want to avoid having two potential superstars fight after only a couple fights. Perhaps the quality of the fighters manager gives them better matchups. An organic world like this where I could take over as any fighter's manager would be a dream come true. I think the current implementation of TBCB is very awkward, but I still enjoy it very much.
Also, KEEP THE GAME LEAN. Take out the DRM!!! This is a simulator, video animations are a complete waste. Instead, have many more fight shots- even better, create something like what tvsports boxing has.
I have many more ideas for improvement, but I think a better foundation should be created first and having a living universe would be a massive improvement.