I don't think Frank Oz should be involved with the Muppets unless he wants to fully commit himself to them. He phoned it in on Muppets From Space and then decided to leave, but still felt the need to comment on the 2011 movie. It would be great if he wanted to work on the Muppets, but he can't have it both ways. He can't not bother to show up to the set on a movie when he's still involved, and then drop in his two cents when he's not a part of things.
I'd say more than just Frank phoned it in in MFS. But he had his foot out the door since the late 80's. Look at how few of his characters appeared on JHH, not to mention how many solo Ernie skits came out near the end of that decade. But MFS must've been the last straw. Considering the problems behind that production, I could see why.
As for his commenting on the 2011 movie, well he was kinda pestered by the reporter. I don't think he wanted to say anything and wanted to focus on
his project, and was a little annoyed by it. Plus he seems to at least have been apologetic about his opinion. And I'd admit, I like TM, but he had a point about the movie being a little too cautious and safe. MMW at least took risks and became a more Muppety film as a result. Even though TM was written for a fan audience in mind, it was the film that they needed to re-establish the brand. That actually
had to be safe/cautious.
I don't think Stoller is going to be involved in any TV show that the Muppets do, and I also don't think that if for some strange reason the Muppets did make another movie that he would not be involved at that ether.
I don't think Stoller would bother with a TV show. I'd see him as a producer, if anything. Maybe come up with a core concept or two. I don't really see the film crew getting involved with the series unless they're that dedicated to it. Seems they'd just make other films over a TV series no matter what.