It isn't innovation from a math sense, it's innovation in a pedagogical sense. Once you've internalized pi (and math in general) it is pretty hard to see what is so difficult about it (a well studied issue with expert knowledge and teaching things to novices). However a simplification from the point of view of the novice who doesn't "just get it" is a good thing.
However a simplification from the point of view of the novice who doesn't "just get it" is a good thing.
Questions about mathematics pedagogy are inherently empirical, and should be answered by observation of actual learners. So where is the evidence that learners who don't get how to use π will be better able to learn mathematics if they use τ to tackle the same problems?
I don't know. Perhaps they are still at the "convince someone to actually try it for an entire n-year math curriculum" stage? It's not like using Tau is something that you can do in class for a week and expect better results. Even if you try the lesser "here's tau, always substitute 2pi with tau" every couple years on a group of students and track them through their math learning, it takes time and a lot of effort to get those numbers.
In the mean time, there is lots of anecdotal evidence of people understanding a lot of concepts easier with it, suggesting these studies be done in a scientific way.
