We won't need a top class AM if we are going to be playing 433 for most of the reason, as Miki and Martial, combined with Rooney & Pogba (possibly) either side of a CM. I think people pay too much attention to footballers having defined roles, like 'deep-lying playmaker' or 'destroyer' etc etc. In a 433 with 3 of Rooney, Schneiderlin, Bastian, Carrick, Herrera, Pogba (possibly), Kroos (possibly), Matuidi (possibly), there's a balance in the team and a good enough mixture of attack and defence in the midfield - the players can share the load going forwards and backwards, which is what most teams do when they play a proper 433 (see Enrique's Barca, Mourinho's RM or the current Germany side when Ozil isn't on the pitch). Miki creates more than most players in Europe, while Martial is also capable of creating as much as he scores, when he's on the left. Ibra, unlike any striker we've had since Berbatov or peak Rooney, can create for himself too if needed.
If Herrera plays the way we know he can (and he deserves a chance to show that, as no player can be judged having only played under LVG, who can make Messi look useless), and Schneiderlin shows his Soton form, we'll be fine. A lot of people forget that Schneiderlin contributed a lot to their forward play, and hasn't shown that side of his game yet here, bar one or two appearances. I think Mourinho's style will suit our current midfielders (not to say we shouldn't sign a new one), because he won't shackle them the way LVG did.
Matuidi is like Schneiderlin in that he isn't an attacking midfielder, but he contributes a lot to how the team attacks. I've watched a lot of PSG over the last two years and his drive/energy going forward causes a lot of trouble for defences (I know they're very different as players, but think a less exciting version of Anderson, who can defend). He is an underrated passer, too.