I guess that might work to aid magicka+stamina hybrids.utility skills to scale off max magicka & max stamina, rather than a single resource.
But because it requires consideration of calculations like that, what I was trying to suggest was making utility skills scale as little as possible, so that they would be equally utilitarian to any build regardless of its stats.This could be a simple addition and divide by two, or a more complex formula biased towards one of the resource stats. This would work for pretty much all utility skills, but the trick would be in getting the correct formula.