That would be welcome, though I like a mix.
I think the complaint is in the scoring. I can set a new record on a 4x4 puzzle, finish it legitimately in 100 seconds, but it hurts my scoring average.
And I can also do poorly on a 4x4, finishing in 220 seconds, and it doesn't hurt my scoring average much more than the record did, but it still helps my completion time average.
I think your solution solves only a piece of the problem. The full solution is in tracking solving times and points differently for each type of puzzle.