Fernandinho spends more time in the attacking third of the opposition pitch than most other teams attacking midfielders, he's got all the license in the world to get forwards and particularly to shoot from around the box.
On top of that, with Kev increasingly going to deeper midfield positions when we are trying to break teams down, you'd get some nice rotation in the midfield without leaving us too exposed.
And of course if we played 352 then you'd have an extra CB to protect against counter attacks while SMS was roving forwards.
I think it could definitely work if we wanted it to. As has been pointed out hundreds of times on this thread already - Fernandinho was a box to box midfielder before he arrived here, not a pivot.