Yeah that art style is really nice. The UI just looks too minimal. There's two "boxes" that aren't even being used. I mean it's good to have something to split the areas up but those areas themselves look like they're saving space.
See, thats the problem, DOTA 2 is supposed to be DOTA - but nicer looking. If the game isn't alot prettier than DOTA then why bother? To be fair that screenshot does look nice (graphically). UI wise though I really would like more.