If they make content in the dungeons worthwhile.

Example: BCNM 30: Peacock charm good until 75 <= keep it capped because it is never negated

Example: Dungeon 30: Drops gear that is good until 50 but 1 level increase will 100% negate it <= do not cap it because the dungeon is a waste of time doing anyways.

I say cap the dungeon and make it where some of the gear is never negated. That way the content piles up.