So, so far I've levelled all classes up to around level 5 and I've taken a real interest into Priest.
I'm still in the process of unlocking all the cards from level up so I'll report back later.
Like getting a class to level 10 gives you a card pack. defeating all expert AI gets you 100 gold ETC
that helps getting some expert cards while you level to get class cards.
UtH has been nerfed now. You can disenchant it for full value.