I agree that Nidhoggr was a huge miss. To me, the 10 mana cap was enough of a debilitation that the force reduction is overkill. They should've gone with one or the other, but not both.

That said, I don't think we should change cards (especially not this drastically) after they're released, even if people think there's a good reason to. It's a slippery slope. I would rather leave it the way it is to avoid setting a precedent that card design is not final and put more pressure on the team to get it right the first time.