should i open a movie review channel on YouTube?

Yes u sould do it. Don't care about the other channels like that on youtube. Make your own and try to be funny and special (That's what most of people likes!). toon us u personality at his best and make it unique. I suggest u to add some movie scenes while u are reviewing. Example: When Kate and Humphrey howls at the moon in the train.
So yeah, u should make one ;)

That sounds like a good idea. Will u review the films u did on Deviantart as well?

Sure. Why not.

Well if you're willing to make a critical review, it's ok...By that I mean, not to tell what u think, but to talk about the flaws and the pros about the movie. Review the movie with a critical look is what I mean

I really don't know right now. DrWolf001's account has been terminated door YouTube ALLEGEDLY because of copyright infringement, even though his videos complied with the law. I would probably tread carefully doing that and be prepared to create a new account on another website should the unthinkable happen.