Crazy Jerome
First Post
I fully understand the "Mother may I" problem that comes with bad GMing but it's a problem with the GM not the game - unless you want to play a boardgame by "the rules".
I don't much care for "Mother may I" rules, usually. But my main problem with them is that they are pure fiat, and thus the players don't know what will work until they ask, and that means they are always asking. That is, even if you have a good DM, "Mother may I " rules can still be a pain.
However, I don't see much of this proposal as "Mother may I," but rather see it as, "You must be this tall." Your six year old can't go on the rollercoaster that requires he be 52 inches tall, but it isn't because the guy checking the tickets has that requirement. And the requirement is clear and easy for the six year old to grasp.
I see difficulty ratings by novice, journeyman, etc. as the same way. The only judgment is back to the DM deciding on borderline, new cases, where they fit in the rating scheme. This is the kind of judgment that a good consistent DM can take advantage of, because over time the players will know most of the time what will work and what won't. As you said, that is the heart of those small negotiations that the DM will have to do one way or the other anyway.