Game is perfectly balanced no matter what you use.
The new character are just different....many are already asking for playable ogres, I asked a Bretonnia knight myself,etc....
It really depends on what ou want to play, but feel free to ignore them.
I’ve completed the game and I used many different parties:
2 Empire captains, glade elf, Dark Elf sorceress
4 glade elves
2 loremasters and 2 Dark Elf soreceress (awesome but difficult)
You can really do what you wish, and you can really personalize your team as much as you want.
I had awesome elven archers, or a super fast melee glade elf that could deathblow everyone and insta kill a stone troll.
Or a dark sorceress that could kill a Minotaur with a single dagger strike.
You will see, items and skills add a ton to the game.