[Den-O]

I wouldn't rule out the possibility entirely but I would also take a very healthy dose of skepticism on the prospect. Takeru Satoh & Yuriko Shiratori are both very far removed from the franchise at this point. He could maybe return given the right circumstance, but I doubt she ever would after her injury & departure from the show. While Kohana's actress could return I doubt that would be much of a draw. So if you take Ryotaro & both Hanas out of the equation you're left with Yuichi Nakamura, Yuto. While he has made new appearances as recently as Super Hero Taisen GP & the Kamen Rider 4 specials, him headlining a Den-O reunion with the Imagin wouldn't quite be the 10th anniversary we've all hoped for. Unless he literally becomes Den-O or something.

As is I'd like to see a reunion happen more than just about anyone. But with the primary actors having moved on for the most part, I wonder how viable such a reunion could be.