Not saying leveling up a pair should make all hands that have a pair in them lvl 2. Maybe a small boost to it, like a lvl 1.5.
I find myself in this issue when playing flush decks. Why should a straight flush be significantly worse hand vs a regular flush with only a few levels. This would also help switching between hand types. Like if one was to start with pairs or 3ofakind and then shifting over to 4 of a kind or full houses instead of just doubling down on a lesser hand because they happened to get some planets at the start.
We also see this mechanic in jokers that refers to hands that contain blank