Ditto, he's called Thorin Brokenshield for a reason. Although, his real strength comes from other heroes giving him leaderships, by himself he is managable. I agree their speed is a bit insane, should probably be as fast as Men, not Elves.
Overall Erebor actually sucks pretty bad right now, the only redeeming quality is the Axe Throwers, who can dominate early game, and obviously Thorin the 3rd who is insanely strong. Once ite gets to late game they fail against most other factions though. so overall they need buffs more than anything.
This really comes from all the armor leaderships, plus tower shields. Ditto nontheless, they are too tanky.
I think battlewagons are in a good spot, bordering on being too strong actually. They have practically no trample deceleration at all, and the barrels deal good damage too.
Well, since this only comes up with Ered Luin, I don't think they should get a speed buff, if anything Ered Luin should be a bit slower.