I don't know that the design of the system is a good idea, but I actually think the 2DS will/should be successful. The only reason I didn't buy a 3DS was because of the price. Now, a system playing all the same games with newer hardware will be available for less money. I don't even care about the 3D personally! To me it has always been a gimmick. It's cool, but you buy a system for the games.
It definitely looks awkward, but I'd still prefer it to a Vita or something. 2 screens vs 1? Hmmmmmm