Not sure if this has been suggested before, but expanding on Famous Battles would be nice. I'm not certain whether they actually do anything beyond giving you a little marker. Things I'd like to see:

* Morale bonus if the winning faction of the famous battle fights on the spot of said battle.
* Or, alternately, morale penalty if the losing faction were to fight in the same situation.
* More detail; maybe a listing of Famous Battles your faction has acquired, with the full details of the battle saved (casualties suffered and inflicted in individual units, length of battle, etcetera).
* I'd find it pretty cool if it automatically saved a recording of Famous Battles, actually.
* Or better yet, save the Famous Battles as Historic Battles with statistics of how the original battle went down. Or, if not Historic, then add a new section for Famous Battles.

Not at all knowledgeable of the effort involved in any of this, or whether some of it is even possible; but, I think it'd be interesting to see.