On "very hard" and late in game (last several missions of story plus end-game content, sidhe shrine scenarios and the like) i started fighting mobs that were not killed in 1-2 attacks or cleaves. They also started to really hurt with their attacks, so off-tanking stopped being viable. Champs could not survive with 2-3 regular mobs on them and could not kill them fast enough, even actual "tanks" struggled. To finish 2nd endgame season I had to remodel my team and use 2 tanks (Mordr and Red Knight), caster for CC and Balin for killstreaks and damage dealing. Most of base-game i had a champ (Black Knight) in my A-team, but in the end he just was not doing enough.
Ah. I have never gotten that far. I think of the several runs I have had, I only got to recruiting Lancelot/Morgana and lost interest. But maybe it is because Old Faith/Righteous seems to be easy mode for the game.
Balin seems like the best knight in the game, so going the opposite way won't be the easy mode.
Wish the game had less trash mobs to fight, so doing another run wouldn't take so much time. If it was a more condensed game I could see myself replaying it to try out the old-faith guys like Guinevere, Faery Knight, righteous guys like Lancelot, or just neutral guys I didn't use now.
The sheer amount of combat probably made them also tune the balance for things dying faster, don't want people waiting for poison to kick in if you got to do it 10 times per mission.