I'm a few years removed from 3D work so take this with a grain of salt especially since today was first time I've seen GITF. I've implemented several 3ds Max Game Asset importer/exporter tools for modding over past decade. While I like the look of GITF 2.0 quite a bit, it does seem to lack a number extension points that I would probably need for a generic importer/exporter for handling game asset round trips (import, edit, export). I would love to handle import/export in a generic way and have tried with FBX and collada to poor effect in the past. Really want to take asset convert to GITF then import to max edit and then export from max to GITF and then finally bake back to game format. The less stuff software you need between the game format and the GITF file the better but should allow for automation/customization.

You can get 80-90% there but miss quite a bit of fine detail needed as a interchange format (which is why this is a transmission format I guess). Extensions seem to be basic and I question how well they work in 3d editors but not really sure how that works and is probably editor specific. I've had a lot of issues trying to have a single file like collada be properly supported in multiple editors unless it was fairly basic model. That leads to a lot of wasted time for modelers trying to get the edited model back into the game and working correctly.

Back to GITF, collision seems to be missing. They admit that they dont have vertex compression implemented or animation for things like material colors or animation metadata (timelines, looping, ...) . Is there a way to describe a partial surface sort of like skinning for other reasons (for example Fallout 4 needs to tag certain surfaces/vertices as to say that they are part of the head or arm for decapitation in game). Anyway looks like a nice start as its all JSON (or binary) unlike GEX,obj,3ds,... which seems to need its own parsers to read and they did only claim to be an transmission format. Again only did cursory read of the format so I might have missed things.