Title says it all, even if motion blur isn't possible as of yet (I know you guys are working on it, and the one in-game is just straight from T3D itself so it's buggy as hell), one thing I look forward to is wheel blur on the rims when you drive fast. Just adds to the immersion.
Would do nicely for photos as well. It's always a shame seeing everyone's dynamic photos but the cars look like they're glued in place.
The issue isn't necessarily just wheel blur, it's motion blur in general. If the effect could be added, we'd likely see less people complaining about physics due to the increased sensation of speed. I personally would love to have an official motion blur effect as it can help smoothen out lower fps, as well as the sensation of speed and visuals.
Assetto Corsa just changes the model and textures for wheel motion blur, so it could be done that way. There are even some mods that already do this like the b 25 mitchell that has motion blur on the propellers.