1. Bill Watterson would never let a Calvin & Hobbes film get made. So stop worrying.
2. Assuming a C&H film were producable, I'd sooner see it as animation than live-action. But if it had to be live-action, have Hobbes animated a la Roger Rabbit instead of CGI'd like Garfield.
Oh, and either Pixar or Studio Ghibli would have to make it.
That is all.
Calvin & Hobbes © Bill Watterson