I don't know. I can't entirely disagree with you, I just feel like with regards to TMNT in general, I sort of know what I'm getting into and just try to enjoy what I'm given rather than bemoan what I was not (MOST of the time). For the most part, I wish TMNT in general wasn't so linked to bad slapstick, dated humor and pizza jokes, and I do wish for it to be presented, generally, in a more sophisticated fashion than it's usually been, but at some point I think I just gave up on that and started taking it for what it is, or at least what the creative powers-that-be want it to be.
With TF, I got exactly what I expected to get and was fine with that. I hadn't seen most of the last 2 or 3 seasons of 2K3, so the stuff that didn't fit didn't bother me, and I was honestly expecting the FW versions to be played down even more than they were. Just because the potential is there to turn something into the equivalent of Shakespeare doesn't mean they have to.
Potentially, sure, we could have had a two-hour epic where all of it was played straight, the FW TMNT characters were seen just as they were in the first mini-series, the 2K3 versions weren't so condescending, and the Mirage ones had a bigger role. Would'a been nice. Sometimes, I just figure, "Eh, close enough." I knew from the start they weren't going to put THAT much work into it.
Again, can't disagree with you opinions. I guess I just settle for less, sometimes. I'm kinda old, it happens.
As far as TMNT in general goes, let's be honest, its entire continued existence is nothing more than "fanservice"; it's not THAT popular and every version since the OT has leaned heavily on referencing/reimagining what came before to sell itself in hopes people who grew up liking it will approve. Isn't that kind of the very definition of "fanservice"?