So we're going through this right now with our kids and it's a little of column A, a little of column B. Yes, kids should learn to be okay with being bored and/or seek out their own projects *and* it's beneficial to be around other kids who are ahead and want to learn more.
"But what do we do with the gifted kids, they'll just sit in class and twiddle their thumbs?" I don't know, I guess it's impossible for them to help their classmates, or work on a project in class that uses their curiosity and also teaches their classmates something. <shrug> Guess we can't!