Most Over/Underrated Class?

[stoutstien]

Stunning strike only works against Constitution Saves.

And a Dungeon Master can add any property to any monster. For example I run Undead with "Immunity to all mind-affecting effects (charms, compulsions, phantasms, patterns, and morale effects).
Immunity to poison, sleep effects, paralysis, stunning, disease, and death effects."

If you change the rules you can't really say that any class/feature is weak/strong. Especially if SS is probably 50% of the monks kit.
The lack of NPCs that have immunity to stun isnt a oversight. Stun is rare, with only 5 spell/effects that can cause it.