7 no-hitters and a shitload of Ks is nothing to sneeze at, to be sure, but in 27 seasons he only one 20+ games twice and 15+ games seven times, not to mention he had 2800 walks in his career, far and away more than anyone else in baseball (Steve Carlton at #2 had nearly 1000 fewer). He never won a CYA either.
He's not a travesty in the hall like, say, Don Sutton, but he wasn't as great as he's made to be either