That's actually a weird how often Vlandia is voted in siege and tdm, even tho they aren't that great anymore, but it doesn't really matter much in the end.
An archer-heavy team composition can win matches with significantly less effort than say a team with a nice balance of infantry/archers/cavalry, and Vlandia's probably the best faction at spamming archers.
I still think that the Sharpshooter could use a bit of a nerf in the form of making longbows his default/faster weapon, with the Arbelist's Hickory Crossbow/Strong Bolt replacing the Arbalest/default bolt combo. This will most likely require a bolt that's stronger than the Strong Bolt to make ammo upgrades on a crossbow perk more meaningful (maybe a damage increase from 76 to 80. For reference, Arbalest w/ standard bolts is 85), though IMO, it should come with the penalty of only having 20 bolts vs the 30/35 found on most quivers.
And if we ignore TaleWorlds' intentional imbalancing regarding archers vs other classes, the Voulgier's probably one of the better shock troops in the game. Sure, their two-handed weapons are slower than most other classes, though I'm starting to think that the Voulge is actually typed as a blunt weapon w/ the cut damage being for cosmetic purposes. Combine that with the fact that it's much faster than every other 2h blunt weapon in the game more than makes up for the lack of crush through damage.
Haven't really found out how to use the billhook effectively, cuz from all the times i used it, it feels like a shadow of its former self back in the peasant shock troop days.
Sergeant is also fairly standard, though the having of the 2H sword perk independent from weapon selections does allow for a lot of flexibility that other classes don't have during infantry v infantry fights (Mace/2h sword to deal with most enemy types, or axe/2h sword if you REALLY don't like shields)
I do agree that some classes could be looked at, however. Can't really comment on the cavalry units since they seem about as samey as the 110 cost archers of other factions.