What makes Murray special is his ability to quickly create space. Second is his quick release. Those two things together are going to be a pain in our @$$ for a long time.
Seems to me that most mobile QBs tend to do better than the pocket types in their rookie season because they can slow the edge rush with threat of their legs. But they also tend to not progress as well in years 2 and 3 because that dependency on gaining those yards on the ground. He will probably win some games he shouldn't for that reason, but it's hard to think that roster will win more than, say, 7 games.
