Looking at the 2nd half of the Utah game (and I know this is a limited stat, but that's what we're talking about here):

Shelley was 10-13 passing for 88 yards (6.7 yds/attempt) with 1 touchdown and no interceptions, and he gained 48 yards rushing on 6 attempts (8 yds/carry) with one sack and one touchdown.

Wilson was 9-13 passing for only 67 yards (5.2 yds/attempt) with a pick-6 and no touchdowns, and he gained only 16 yards rushing on 7 attempts (2.2 yds/carry) with two sacks and no touchdowns.

Even if we look at the full game stats, Wilson was not significantly better than Shelley. Overall, I'd go with the QB who led four straight scoring drives in the second half to win the game over the QB who threw more TDs for the other team than their own.