The change is a major redesign of the rule. In D&D terms, moving something from the GM's authority to the player's authority -- to the point that other suggestions to do so are often strongly objected to (and this one is, as well, given how often it's contested on these boards) is a pretty large change. This isn't an incremental improvement, it's a redesign the makes the rule be fundamentally different.
So, if it's a good rule, but improving it requires a fundamental change to the rule, I'm kinda stuck reconciling this. It's not like you've given the rule a nudge, you've effectively rewritten the entire rule.