First off, I agree with you that MMO's are grindfests, and that grinding just isn't very much fun no matter how they couch it. EVE has perhaps the best idea, in that your character gains XP just by being there. You don't have to do anything, and can just get on with the game. The downside to that is that anyone can be a high level as long as they don't quit before they automatically get the level, which means that the morons who want everything handed to them can be right there with the serious gameplay people.
But what you wrote can be applied to just about any video game, from Pac-Man on up. Even an intensely story-driven game like KOTOR still had leveling, and there were parts of the game that were difficult to get through unless you decided to grind by killing the same guys over and over again to advance your level, or your money, or whatever you needed at the time.