I think the Grail Knight is a great addition, really fun to play.
What I like the most is the quests, it’s a small thing but adds so much to the feeling of the a Knight on a quest.
Same thing goes for the challenges to unlock the cosmetics, I love them.
The only feedback I would give is that I would have liked to see more cosmetics that you unlock from doing challenges on higher difficulties. For example Tis But A Scratch! - Complete a map without falling below 90& health as a Grail Knight. One for completing it on Champion, on for Legendary & one for Cataclysm.*
Some people did not like that the Career & cosmetics was sold separately and on top of that you have to unlock the cosmetics. I completely understand where they are coming from but I honestly do not mind it.
I play Vermintide 2 a lot, I soon have 1000 hours in the game and 11-12 euro is not much considering all the hours I have in the game. On top of that they have added, free missions, I can play mission dlc’s even if I do not own them (I do) as long as one in the party have them, they added Beastmen for free & they keep adding cosmetics you can buy for in game currency. So I personally do not mind paying 12 euro for a career and cosmetics.