Level will be more important than real troop value. So all faction could perform quite good and their victory being more a matter of good luck (backstabbing someone already at war on many fronts, then finishing his enemies).
Battania 2019 troop tree seems very bad: zero archers. They get both a spear infantry and a infantry with javelins, shield and short weapon. Archers only among nobles. Also the cavalry is still weak but they get it from tier 4 while they could have an early weak cavalry in 2018 troop tree.
Maybe being tribal will have as many nobles as standard troops? It would be very strange to be out...bowed by other factions since they are supposed to be already outhorsed.
Empire won't have cavalry with shield on base tree. They will use their horse archers that have a spear too so charging archers will be risk. Their equites have a shield and I suspect that is the weakest of the noble troops that will evolve in cataphract and lose the shield since evolving a noble cavalry without shield could be difficult when armor is weaker, otherwise the equites could be a noble troop of the subfaction of legion of betrayed. Anyway their legionary seems more armored to other basic infantry so despite the description of being well rounded empire seems to have very strong infantry and the advantage of having both archers and crossbowmen while they lack a proper melee cavalry.
Aserai is a mistery....seriously the wiki says 2 melee cavalry, 1 horse archers and 1 foot archer but that is the khul slave special troop.
Sturgia basic spearman will lose the spear and get the longaxe, seems nearly as armored as the empire counterpart and their berserker will be very strong since there is the old video of cutting two horses in one attack. They also have huskarls as noble troops that defeated triari (the elite foot troop of legion of betrayed) and I guess some heavy noble cavalry. Archer will be their weak point but at least they upgrade the hunter. Bringand won't be an option but only a passage to get your medium cavalry.
Vlandia seems to have a solid troop tree and a great noble troop tree. They lack rate of fire because no archers (only their Robin Hood subfaction will get them).
Khuzait troop tree feature very well armored horse archers and also they get heavy cavalry in their basic tree, so if you want to go Swadian massing knights you can use khuzait and mass heavy lancers. Their infantry seems good too while their archer seems less armored than Vlandian or Empire