I'm not sold completely on Croyle, either, but I'm not convinced he's doomed to be terrible either. The guy shows sparks of potential, even with a line that can't protect him 85% of the time.
But several things need to happen. Croyle needs a better QB coach, a competent line needs to be set in place, and Huard needs to be dumped in favor of a veteran quarterback that has actually started games for most of his career. Brodie's not going to learn anything valuable from a career back up, and he's not going to learn anything if he's constantly on the turf looking up.