Alright, there's been a platformer creation game. As I said before, it makes no difference. If all LBP were was a second-rate Mario game where you get to choose the locations of the platforms, nobody would care about it. But when you slap on an amazing visual style, cooperative gameplay, and the ability to make complex puzzles and machines, it becomes something else entirely.
Not even close. But on the other hand, if you take another generic FPS, add armor levels and jetpacks (been done in platformers for ages), and focus exclusively on the multiplayer experience (MUDs were already old news), suddenly you've got Starsiege: Tribes.
Or say you want to make a sim game. They've been around for ages, at all levels of focus. The microscopic level in Flow, the interpersonal level in The Sims, the urban level in Sim City, the conflict level in Civilization, the global level in SimEarth, and so on. Character creation has also been around for ages, as you've pointed out. And procedural animation? Meh, we saw that in PC games 10 years ago. But combine them all into one seamless package and, holy crap, you've got Spore. There's not an original element in the game, but who would claim it's not amazing and revolutionary?
Or, take the learning AI characters from ancient PC games, and ramp up the sophistication. Steal a bunch of gameplay from Populous, and throw in some city management stuff from SimCity. Combine them together and put in a morality system swiped from some game on the Sega Genesis. Suddenly these elements are all working together in a new way: your learning AI character actually has a purpose that motivates you to use it, the god setting makes the morality system challenge you in ways it never has before, and you've got Black & White. Now, take a bunch of those same ideas and toss them into an RPG, and you get something else entirely: now it's Fable.
Do you see what I'm getting at? I bet you could do a similar deconstruction with every revolutionary game of the last 20 years. (It's true that those last two both turned into disappointments, but only because they didn't live up to the concept they promised. You can't deny the concepts themselves were revolutionary. I also think it's no coincidence that they were made by some of the same people making LBP).
Now, take the level design mode that goes back at least as far as Excite Bike. Take the physics system/complex machine builder we saw 20 years ago in The Incredible Machine (more recently in Armadillo Run, a great indie PC game). But take them, and put them together in a new way somewhere we haven't seen them before. Put them in a platformer! Now, instead of just passively watching your machines work, you actually interact with them with a little character. Now you have the classic platformer goal of getting past these obstacles to put everything in an entirely new context. And you've got other players to go along with you. By the combination of old elements, you've created something entirely new. It's LittleBigPlanet.
If you haven't seen why LBP is unique yet, I don't think I'll be able to convince you. You can go on believing that the only reason every journalist and game dev who's seen it has called it amazing, and revolutionary, and predicted GOTY awards for it, is because they haven't seen this... thing:

That's where LBP is unique. It's not just the editor, it's how the editor is implemented and how it's almost seamlessly integrated with the core platforming gameplay. I haven't EVER seen an editor like the one in LBP used in a console game. The closest thing to it is Spore, but Spore isn't a platformer, and the editor isn't as seamlessly integrated into the core gameplay as it is in LBP(at least from what I've seen)
See, this guy gets it. But it's not just the implementation of the level editor. It's also the gameplay that's so new and fresh even before you know the editor exists.







