Eastman has gone on record saying that a more adult-oriented show should be the next step for the turtles, somewhat akin to the Netflix Daredevil series, especially seeing as the TMNT was originally intended for an older audience. We've gotten quite a slew of shows oriented mainly to a younger audience, and although the 2003 series borrowed beats from the original comics and could therefore be considered adult-oriented, it was still a kid-friendly show, so I'm positive we'll eventually get one based primarily around the original incarnation of the turtles...or some facsimile at the very least. Whether animated or live-action, I would definitely love to see that happen.