best idea...
 

i think the best idea that would really work well with the turtles would be a Lego style game like lego star wars. the game would allow for some great humor and appeal to a wide age range.

At least then they could go back to the beat'em up formula. Maybe Mega blocks, Legos suck for turtles.

TMNT: Legends, a "beat 'um up" game that has multiple levels, one for each incarnation of the TMNT. You could have a Mirage Vol 1, Vol 2, Image, Mirage Vol 4, Archie, OT, NT:TNM, 2k3, and even >> and the 4 movies. It'd almost be a TMNT equivalent of Mickey Mania, following the TMNT through their creation until the present.

In thinking of the game I thought each level could have 3 stages. In stage 1 you choose your Turtle (or even character, who knows), stage 2 would be a stage where you play as a specific character (like Venus in the NT:TNM level or Raph in the movie 1 and maybe even volume 1 levels. [Because I thought making the 1st level the first issue would be fun, Stage 1: TMNT vs. Purple Dragons, Stage 2: Raph infiltrates the Foot HQ, Stage 3: TMNT vs. Foot and Shredder]) and the 3rd stage you would again choose your character.

I think the art style should also follow the progression. Like level one could be in gray scale save the red of the TMNT's bandannas, and drawn in the early E&L style, and so on.

Also I feel that Konami should be given the license back. Their games from the 80's/90's were great.

Great ideas, but I still think a TMNT game using the mechanics from the Ninja Gaiden series would be tops.

I still like to fantasize about Naughty Dog (of Crash Bandicoot and Jak & Daxter fame) making a TMNT game. It would be a free roamer, of course, with an interactive environment and a really cool story.