I'm not sure everyone realizes how ridiculous it is to have Gibbs and Milroe back there together.
Imagine you are the defense, how are you going to handle all the various scenarios? The situation creates space for Gibbs, and Gibbs is one of the best in college football in space. You have to respect Milroe's running ability though, so you can't just focus on Gibbs. Even if Milroe keeps the ball, the offense can still do pretty much what ever they want. Milroe can run, he can dump it off to Gibbs, he can pass downfield.
They are just such complimentary players, obviously Milroe is not as good as Young, but I could argue that he opens up more opportunities for Gibbs than Young did.