Okay, having tried the Noire build (thank you, srb2bld!), I turned off bot rubberband boost, as well as basically disabling all of the Rival "cheat" options. After playing a few cups...
I gotta say, while nerfing the CPUs like this certainly makes completing cups on Intense less stressful, it absolutely doesn't make them unchallenging (on most tracks, at least). In fact, they're still very capable of making sure you don't feel remotely comfortable in first, which speaks a lot as to how aggressive the CPUs are. It feels a lot fairer, but still fairly challenging.
(I will admit that I did turn off lives for getting the last few Super Emeralds, though. Considering how insanely hard those stages are, redoing an entire cup just to take another crack at them feels like the height of insanity. Noooo thank you, I value my time and sanity much more than that.)