Some thoughts about new version of your mod.

Saracens - Hard - Huge - loyalty:130

I chose Saracens because I wanted silent place as far away from the "action" as possible.
Now, about 100 years past and there are some problems with the campaign mode. The main problem is that nothing really happens. Factions have hard time to gather enough cash to build significant army and move somewhere. This mainly concerns "one province" factions: Russia, Denmark, Aragon. Spain and Sicily have nearly the same situation. Spain (not being attacked by anyone) finally after 80 years managed to conquer Navarre. Almohads constantly fights with rebels in Portugal. The worst situation is on the east. Provinces to the east from the Lithuania-Kiev line have never seen any enemy army. Russians like other small factions are not able to expand due to high cost of their royal units. They have 10 druzhinas and 6 other units (vikings, horse archers, etc.). All these units make Novgorod exactly 130% loyal. All surrounding provinces are owned by not so powerful rebels. Russians have many opportunities but not enough cash to recruit troops and move somewhere. The same for Denmark ("free" Sweden and Norway) and Aragon (Navarre, Valencia). Poland fights with notorious rebellions in Pomerania and Prussia.
Factions that have more provinces (France, HRE) or are naval/trade oriented (England, Italy) can handle the situation better but they are still very slow.

All problems vanishes when you play with default unit size. It clearly shows that AI was designed for smaller units' size. AI has huge problems with managing big, costly units. IMO reducing the units' cost should help.

Tactical mode is another story. You did truly great job with tweaking units behavior. AI can still be outmaneuvered but it tries to keep right order/formation for the most of the time.

I think I'll try another campaign to see if it will go the same way. Russians look interesting and challenging.