Doug Belgrad, Columbia Pictures’ president said that director Marc Webb might not be back for The Amazing Spider-man 2, NOT because the movie wasn’t great and definitely NOT because of all the issues the execs at Columbia Pictures found with the movie :
We’d really like him back, but there are obstacles. He has an obligation to Fox.
Webb signed a contract to make (500) Days of Summer, which contractually obligates him to head another project for Fox soon, which could cause conflicting scheduling problems. [Hollywood Reporter]