I believe that a more nimble QB could have avoided getting hit the way Bradford got hit when he tore his ACL. Sam was running to the sideline and did a pump fake which slowed him down a bit, then he tried to get out of bounds before getting getting hit but exposed the back of his legs. That doesn't happen to a guy like Russell Wilson. Wilson is slippery as heck; Bradford is the furthest thing from slippery that you will see at the QB position since Drew Bledsoe.
As far as his bad habits, they were talked about by Mike Martz, who said Sam developed some bad habits because of his poor protection and bad receivers. So this is not a new issue. Sam has had some problems with his accuracy, notably in the Dallas game and especially in the SF game. Fisher had said that Sams footwork was getting better, so you wonder how the ACL will affect that.