I have a few suggestions,
New Factions: Sweden and Georgia or Syria or Armenia (Just another faction in the middle-east, one that may be friendly to the crusader states as I see them die too soon even with my(France) intervention) and too many times I see one Muslim faction unite all of outremer and become a super block in itself (at least til the mongols come and then they take over that role)
Unit Roster: We have to many of the same unit with just a different picture and a few minor stats
Suggustions, Spearmen, Prussian Axemen(just a crappier version of Dismounted Huscarls), Battlefield Assassins (fictional and useless) Peasant Archers- Peasant Crossbowmen (Militias make up for these) Reduce the Horse Archer Mercs in Anatolia Turkomans would suffice for them.
Possible Unions: Only if Sweden and Georgia cant be implemented, Kalmar Union OR atleast Denmark-Norway and Poland-Lithuanian Common Wealth.
Possible Emergent Faction: Instead of making Bulgaria just spawned rebels for the Eastern Roman Empire and Hungary why not just have them emerge a brand new faction (Tsardom of Bulgaria) This would make life even harder for the balkan nations (the way I like it) other than this actually the best mod out their hands down. Only one that can even come close is Third Age and that isnt Europe.