Probably Legionaries and Triariis for the infantry but i did not fight with or against the elite Sturgian units since they were buffed apparently but the Empire should have the best infantry. Just my guess though.
Last I recall, Triaii suck. Like most minor faction troops, they were nerfed down to match their tier, and so they're practically worthless. Far better off with legionaries. Sturgia has the more brutal infantry and tends to get the better of the Empire in melee, but Empire has them beat in terms of armour, which is more than enough reason to use them if you want more of an 'anvil'.
Vlandia has decent cav overall, they do the job but the Empire cataphracts are probably ay least as good, i dont know exactly but it feels like it, i may be wrong. I would say all factions except Battania have elite cav units that work well ( though it is worth pointing out that Battania s cav have long lances so they are good on the charge against other cav initially)
Vlandian cavalry is in a seriously sorry state, however Banner Knights are capable of dealing more damage on a charge compared to Cataphracts. Battanian cavalry do get underestimated, but yeah, they can be deceptively good. Too many of them in the common troop tree though, its weird the archer faction lacks archers.
For archers, if we exclude fian, i actually dont know who is second best so i would be curious to know, i am guessing the most heavily armored elite archer unit probably wins but i dont know who s got the best armour between Aserai master archers, Khuzait marskman and Palatine guards and who s got the best stats in melee.
Palatine Guards, even after their nerf, are still the most heavily armoured archer in the game. They also have better than average skills for whatever reason, and are easier to train. Their issues are mainly their average bows and their single quiver. Khuzait marksmen are average everywhere save for a good bow, although they're not to be underestimated. Statistically, its the Aserai Master Archer which is the best standard archer. Good armour, great skills, great bow and two quivers of good arrows. All they lack is trainability- Aserai only gain archers at t4.
For Horse archers if we exclude khan guards, i dont know either who s better between mameluks, heavy khuzait horse archers or bucelariis, maybe it is very close.
For real horse archers, the Khuzait ones are obviously best. Buccellarii are good, but like all Empire troops, they favour defence for offence. Mameluke heavy cavalry are amazing in their own right, they've got a versatile kit that lets them carry out a variety of roles. They might not be what you want if you only want a horse archer though.
For heavy infantry i would say between Battania and Aserai palace guards but maybe the Sturgians and Vlandians 2handed units are better than i think.
Do you mean shock infantry? Because most 2hander troops aren't well armoured. That being said, its a bit of a toss up here. Its more of a preference between polearm vs 2hander axe- pole arms are longer, while axes cleave and have axe properties. Otherwise, they both do huge damage, but melt against ranged units.
Vet Falxmen have A LOT of throwing axes, but they'll do poorly against more dedicated skirmishers. They don't have great armour, but their bundles of axes does let them seriously **** up other shock troops.
Ulfhednar and Shock Troops basically boils down to whether you like more heavily armoured polearm troops, or a glass cannon with crazy stats and axes.
Menavliatons are the most heavily armoured polearm troop, but again they sacrifice killing power.
Palace Guard are the most heavily armoured axe troop, and are seriously scary. They lack the super man stats of the Ulfhednar though, which makes them less killy.
Voulgiers look to be the 'middle of the road' option out of all of them, but a lot of people reckon they're the best.
For a bonus, I'll add in dismounted Khan's Guard. These guys will move slowly compared to everyone else, but they've got great armour and the best stats. Not to mention their bow.