It’s not about that. I mean, McCree is okay as he is now. But he is, at least in my eyes, the only DPS with no interesting mobility mechanics. He is such a situational pick at the moment.
Against a tank heavy comp, his ultimate is maybe the worst in the game. He’s also very healing reliable: he cannot really roll to safety, nor can he heal himself.
All other DPS’ers have a way more interesting kit:
Doomfist: extra shielding /w landing skills, incredible mobility
Genji: deflect, wall climb, double jump
Soldier: healingsss and runninggsss
Sombra: health pack hacks, invisibility and faster running and translocator
Tracer: blinks and recall
Pharah: can fly and boop herself away
Reaper: fades (cannot take damage) and automatically reloads, teleport
McCree: flashbang. Ow, and I can roll, but I often die while doing so.