Just a hand full have been mediocre at best and I mean a small hand full. The majority have just sucked.
Here's a site with a rundown of the top 32 and if blizzard is putting in 100 million to make the film and you go off just past movies, then they are already losing money.
Check it here:
The CGI stuff blizzard makes is to good to discount it and do a live action movie with a very high chance to fail.
EDIT: Looking at those numbers is kinda sad. Seeing that for all 32 movies, one comic book adaption of the avengers grossed more than all of them.