Make 3D its own separate software that integrates with AE, not an AE feature.

 AE's 3D tools are stuck in 1996 because they are a discreet effect and controlled as such. Proper 3D VFX workflows require a good deal of flexibility, an entire monitor full of options, shaders, baking, export forms, VFX standards adherence, 3D data I/O, etc. Worst of all, AE isn't even true 3D. It's 2.5D, and the decrepit codebase can't really be changed without essentially building a new software.

Heck, Adobe owns substance 3D now, but to my knowledge has no software that really integrates with it, and instead has left it a messy toolbox of loosely related software with similar UI, and each has one main feature that most 3D software just put together to speed things up.

 instead of trying to jam 3D into compositing software, make 3D VFX a new software, and make importing the renders, or rendering linked data, very robust. We're talking better handling for image seuences, color space transforms, LUT's, EXR handling, deep image format, 3D track export, the works. Maybe something that can actually compete with... well, at least be compared to modern workflows.