Well theres only so much you can do with an NDS. It was legendary when it came out. Now it's like a gameboy color compared to other consoles.
The ds was (and still is) capable of plenty enough. It all comes down to innovation. Do you think the graphics are holding it back? Hell no, it's mostly the developers lack of said innovation.
All though Capcom may never make this: there's still the next Phoenix Wright Game that was announced in 2007 then forgetten... what a shame
I see. Well either way if the problems aren't being addressed then the console will die anyways. Hell maybe the developers themselves are waiting for the 3DS to see what it's capable of and take a crack at something new.