This is perfect timing, as I'm just now getting back into TB 2.5. I've never been able to get off the ground, even though I've owned the game for years. I've never gotten to the point where I've even had a fight in a universe yet.
I'm really looking forward to this. I just read all 9 pages of threads, here are a few things I'd love to see. Just suggestions, since that's what you were asking for.
I second the idea of 'any' start date. Having this as an initial input would be nice. I want to start with Yankee Sullivan and Tim Hyer back in the 1840s, for example.
I would like the option to bring fighters in chronologically, not randomly. So the ability to include a career start year with the fighter's name, and then those fighters would automatically be brought to active in the correct (user specified) year. They wouldn't all have to go active January 1. Say 1/12 of them come in (randomly) in January, another 1/12 in February, etc.. Or is there a time of year where most boxers go pro (like baseball players in June, or football players in September)? I'm a fan of boxing, but not a freak, it's a passing interest that I'm trying to improve upon . . .
The ability to set beginning/pre-prime/prime/post-prime/end to whatever the user wants in terms of fights years (so you could say 2 years or 5-8 fights before going from beginning to pre-prime, for example). At least being able to do this globally, but it would be really cool to be able to set this for each fighter individually if you wanted to.
Seems like the option to override the schedule, either to cancel a fight you don't want to see, or add a fight that you want to see would be good.
Along those same lines, what about a user specified time frame where the champ must fight the number one contender, say once every 12, 18, 24 months (whatever the user wants). That would solve the 6-year issue if a God (is that a good name for universe controller?

) wants it that way.
I can't wait to play with this. This might finally allow me to get off the ground.
If I think of others, I'll let you know. I tend to be a decent 'idea' guy when it comes to this stuff, I've start several themed baseball leagues etc.. I'm not a great doer, probably because my ideas tend to be too big to get off the ground.
Thanks for providing this.