I have had this discussion a lot, and in fact I made a document a couple years ago when the “Rumor” for VEX U was to become the VEX Unlimited Division. Which is essentially what VEX U finally became (Other then it is only locked down to college now).
I think being able to 3D print is only quarter of the equation to cleaning up the robot designs. I think the one quarter is the craftsmanship, another part would be machining (CNC), and finally cable, program management, good sensor and motor placement with a engineer notebook to really finish off a good robot. Having the ability to CNC items along with 3D printing is an amazing feature.
When I competed (a few years ago now) every time we would make a hole we would throw the piece in a vise on the drill press, no doing it with the dewalt. This kept everything super straight, we would de-bur the metal on the press right away and finish it up with a table top grinding wheel. I know of teams that even go as far as putting items on a CNC to make sure the modifications are very tight tolerance.