Tried the demo but it just felt like Mortal Kombat, I don't mean that in a bad way but it's just I've got MK and barely played it. Fighting games aren't for me, too much button bashing, cramped wrists and memorising combos.
DC could do with more individual character games but the difficulty they have are the powersets. The most popular DC characters are flyers and flying characters are really difficult to build a compelling game around. This is why games like Arkham Asylum, Spider-man 2 work as good games, they characters can soar through a city but they have limits and every game environment needs limits.
A green lantern game set in space could be interesting, the Sinestro corps war? You could select from Hal, John, Kyle & Guy. Each character would have their own power moves and the developers could clean up with DLC to download alternative character skins, given the size of the GL army they'd be onto a winner. Thing is I'd want god of war style gameplay