If I make a 40 wizard (or even a full fort save class) toon with every possible feat and item: strong soul, luck of heroes, great fort, epic fort, 6 great con, 10 stat increases in con and every possible gear item that gives me +fort, and use endurance, and start with 20 con...
I still can't resist your 60 dc stunning all the time, if only there were a half dozen spells that could remove the effect, 1 that makes me immune, or a _CRAFTED_ item that could remove the effect maybe then I would think stunning fist was a fair ability and not have to complain on the forums

There are ways to be immune to fist, bigby, wof, hips, assassin instajib, barb fear, harper sleep, and anything else viewed as powerful, just because you can't do it all in 1 build (no matter how many feats you throw at it) doesn't mean something is unbalanced.