Bear in mind that Rooney will be dumped out of the team sooner rather than later if he doesn't perform (there's a decent chance of this happening IMO, Jose won't persisit with him for long if he's churning. This would free up Pogba for a Lampard/Gerrard style role and create another role in the team for someone like Herrera to operate in. I'd hold on to him for the time being.
I'd like to see Pogba in that kind of role for us, but he's such a complete midfielder that it'd almost be a waste of what he has to offer playing a box to box role from central midfield. One of his best qualities is his ability to bring the ball up the pitch from deep. We've been missing a central midfielder that can do that in what seems like forever.