You can actually buy speed cubes which the center squares can be pulled off so that you can adjust the tension on the cube with a screw driver. It'd be pretty easy to modify the machine turn the cube with the center caps pulled off without having to actually modify the cube itself. I personally still feel like that is cheating.
I think this comes down to this; either you think the act of solving the cube is impressive, or you think the ability to turn the cube quickly is impressive. As someone who can solve the cube in 40-45 seconds (and I'm admittedly pretty slow), the part that really bogs me down is I'm not good at finger tricks or turning the cube quickly. If I had a device (other than my fingers) which would let me turn the cube more quickly, I'm sure I could probably cut my solve times down dramatically. Solving the cube itself isn't all that interesting.