I suggest that the current team bonus be removed entirely(currently gives 5 pop per certain military buildings) - replace it with orthodoxy (+3/3 armor to all monks within the team)
The unique tech might be replaced with something more useful - for instance
Scorpion Line gains +10 bonus damage vs cavalry
(Or however much keeps them balanced yet not op)
Siege Weapons gain x2 pop space and may garrison in castles and siege workshops
Siege Weapons no longer take bonus damage(or half)
Infantry + movement speed and plus additional bonus dmg vs buildings
Feel free to suggest any preferred bonuses or tech affects.
I like the current bonus. It’s a neat little bonus for early rush plays, just quietly helping you out. Also nice when the map is a bit cramped, saving you a bit of space.
+3/+3 on all monks would be brutally OP, Aztec monks with +3/+3 would be unstoppable
Archer/Cav-Archer line is usually a relatively effective counter to Monks. If monks get a bunch of pierce armor, then your only option is light cav. Which may not always be able to close in on them effectively.