i was expecting them to be similar to the Green Knight, and be a Max Level sort of Lord/Hero that you get for a short time.
The fact they don't have a Skill Tree, personally makes them weaker IMO. Specially Gotrek.
As he doesn't bring bonuses to units (the least i expect him was to give a big morale buff to everyone)
And most importantly, no Civic Tree, means this army will always come at full cost.
And this game is not the type of game where you can have countless armies, unlike other Total War games.
I feel they are good in the Battlefield. But in Campaign they don't bring anything special and in fact hit your economy quite hard.