I know Mangini's not a genius, but aside from his own career moves, he's not a total idiot. How do we know Hobson will make a good ILB?
I've seen all manner of quotes so far from people saying he's a good ILB (not you, Pony, an earlier quote) to the expectation that he'll play ILB. From Reiss today, he played OLB in Herm's 4-3 and Mangini's 3-4, and from an old NFL draft report, he played OLB in college.
So, at least he's not converting from DE like Monty Beisel, but we know that Vrabel struggled with the conversion from OLB and he was already familiar with the Patriot's LB scheme. Vrabel did exceptionally well, but it wasn't easy. AD also struggled and also did pretty well, but it also wasn't easy, even though he came from a 3-4 and has tremendous physical talent. And guys like Chad Brown and Beisel did less well, to be kind.
I know we're all reading that with his height and short arms and blocky build and more quickness than speed, he's better suited to ILB. Makes sense. OTOH, if you want the most success on day one of a one year contract, you might start him at OLB and put AD back inside, which he already knows how to play. Then draft a real top-of-the-line speed rusher who can back up Hobson and be the starter next year and you've got your progression.
That makes more sense to me than this fan movement to ILB.