It is a pretty boring monster, but look at older versions of it, they aren't really any better. Really how do you make a top level epic monster that is essentially just a giant turtle with a gland problem exciting? Its quite possible, but I think you can't do it by treating it like an ordinary monster. It should be some sort of titanic challenge or something. Just climbing up the thing's foot to where you can get to any vital part could be a real serious problem.
I don't know about that. The 2e monster manual (compendium?), which is where I remember it from was pretty cool. It was pretty basic, but what monster wasn't back then, but still had some interesting things you had to do to kill it.
The Tarrasque needs someone to take ownership of it and turn it into a cool monster, creating a better story and better powers with more exciting mechanics than what 3e or 4e have done. It should be far more unique playwise than anything else out there.