Well, depending on how it is viewed, Versailles either didn't do enough, or was too harsh.

That aside, the issue was that Germany was insufficiently demilitarized, and the ultimate failure of Versailles was that it didn't break the military culture of Germany. Even if you took Hitler out of the picture there was still plans on the books having Germany rearm and re-militarize, which, at the bare minimum, implies aggressive action.

Ultimately though when it comes to an entire society you're tugging at a complex yarn. You most certainly couldn't unify an entire country behind their treatment over a war-ending treaty. Heck, the Nazi party didn't get the majority vote, so the net result of Hitler's platform didn't resonate that much with the public. Its difficult to look at one thing and say, "Aha! This is what cause that thing to happen." Versailles might have helped set the stage but it certainly wasn't a one-man act.