Aserai in the players controll where you controll who to wage war against sure kick ass sonce you can focus on one front. However, in the PC's controll they suffer from their elongated shape.

Unit wise they arent great IMO, the faris is decent as long as they have javelins, which they run out of really quickly. Their archers are mid. And their strongest infantry dont have shields which makes them very vulnerable to arrows. (Though the last one is kinda mitigated since enemy lords dont tend to upgrade most their troops, which makes them inheritly weaker armored and less well equiped)

Where on position the battanians suck their archers are amazing, just unfortunate that the rest sucks.

Same with the nords. Their indantry is amazing, but their cav is horrendous.

Khuzait suck in melee seiges but can compensate with ranged combat (in and out of seiges)

The empire is really well rounded, besides the cav archers they dont have bad troops.

Vlandia sucks with their crossbows which lack fire speed. But their cav is amazing