And as far as the OP goes, I understand wanting to not be bored in low level dungeons, but what will wind up happening is people killing monsters so fast, that a lot of jobs can't be played in a satisfying way.

Think of deep dungeons. Up until the 101+ and 31+ floors, monsters die so fast in them, that you never get to use all of your abilities until the boss floors. This remains true for a long time in both, and it makes them really annoying to play in, at times. For instance, Wildfire on MCH can barely be used on trash, even into very deep floors, without actually detonating it early manually.

It's better if we just take it in stride, the old content dies so fast anyway.