There's some problems with that, even though i would like to see a local converter, too.
Correct me if i am wrong, but this is my perspective on the matter.
1. The source code - it opens up a possibility to reverse engineer the underlying code structure the game uses for the Cobra Engine. Of course it wouldn't give away too much, but enough for other companies to stoop into the Engine's "logic"
2. Security and Tampering (Moderation) - If you compare it to, say, Second Life, SL has and always had an open structure, the downfall was, anyone could grab the 3D data AND the textures by simply grabbing it off the data stream, And LindenLabs never cared to add encryption. With PlanCo, TMT converts into a in-house filetype container (.pcugc), this is actually a good thing because that's exactly why i stopped creating assets in SL. (It's really painful to see others cashing in on YOUR hard work, and nothing you can do about it without having an (expensive) army of lawyers at your expense. I've created about 20.000 assets in 6 years of my SL "life" (models and textures (no, i am not joking)) and almost all of them could be found in others' shops. If their (the people who copied your assets) jurisdiction is some exotic country, or even another yountry than your own, good luck in getting your justice. I actually like how they've set up TMT and how it's not so easy to "grab" the 3D data. Localizing it would endanger this kind of structure and it wouldn't take long until someone modded a tool to grab the models (and let's not forget the vanilla content, Sam & Co. wouldn't risk any vulnerabilites to the PlanCo assets that are preventable)
And let's assume someone uploaded a , if the TMT was local, they couldn't properly moderate on their terms.
I'd rather see the bugs vanish soon, but maybe a good middle way would be a Viewer of some kind, like a small prog that could display the asset with it's ingame shading properties without actually converting the .fbx