Monsters probably shouldn't get increased health, only damage, to account for players getting stronger.
Maybe base the stats/stat names off Ops and Tactics a bit? Idk.
Agility could increases sprint duration instead of just plainly increasing stamina amount and regen speed. Could also have dash get its cost decreased by a log curve or something, then sprint time keeps going up but dash hits a min cost cap.
Strength stat could also increase melee damage up to a cap