Marino was a great passer, one of the best ever, however, he couldn't run to save himself. That is no crime, just fact, and it certainly didn't stop him from having a great career.
Elway, whilst not in the class of a Steve Young or a present day Mike Vick as a runner, was great on his feet. His run for a 1st down in SB 32, where he did the helicopter impersonation, will never be forgotten. He also had a receiving TD during his career.