I'm not convinced Hutch is going to be better than a #4. He had his struggles in 2014 and after his first full year through the league, hitters will fare better against him in 2015. His stuff is not overpowering and he will succeed when his command is on, but often is not. Stroman has dynamite stuff, not concerned about him at all.
SP worries more than RP for 2015. Cannot expect the same good health, and real risk of a drop in results from those not named Stroman and Sanchez.