People are working on recovering PBR properties, rigging, and editing. I think those are all solveable over time. I wouldn't start a big project with it today, but maybe in a couple years.

If you want a real cursed problem for Gaussian splats though: global illumination. People have decomposed splat models into separate global and PBR colors, but I have no clue how you'd figure out where that global illumination came from, let alone recompute it for a new lighting situation.