So... zero people?

Look, we don't write JJ2+ in assembly for the most part. Bits and pieces for convenience, yes, but most of it is C++. There haven't been any new changes to the JJ2 exe in years (actually blur never gave us the code for doing that), everything gets implemented in the dll. If a system were made for improving the graphics, I don't see any reason we'd want it to be optional. Alternate enemy routines is what Angelscript is for.

Would letting people write C++ instead of AngelScript for certain isolated parts of the game be, in principle, an improvement in speed and/or functionality? Sure, a little. But it would be substantially more work than gain, and the problems you seem to be trying to address feel like they're either already solved or never existed to begin with.