We're playing the wish list game, which is entirely appropriate for a poster forum, but let's start with assumptions before moving to acquisitions.
Let's assume we keep Rooney and he plays at peak form without significant injury/suspension interrupted.
Let's assume we dispose of Ando but that Nani takes the deal in front of him and stays on.
Let's assume Fletcher will never play for us again.
Let's assume no Ronaldo...or no Bale.
Let's assume Zaha is not loaned out and joins the first team.
Those are three debatable, yet reasonable, assumptions. Our weakest area this season was our wing play (and yet still lapped the field in the prem), but if we can assume that was an aberration and that there will be no Ronaldo/Bale gambit and that Zaha will bring the goods, then we absolutely should address the missing piece of the puzzle -- central midfield.
With that, I join the chorus here: a playmaking/scoring attacking midfield such as Fabregas. I can't even believe this is a possibility, but it appears to be a real possibility that we can land Fabregas. He's only 26, so there's no issue whatsoever with his age and we all know his proven worth in the prem. Since I don't get to watch the Dutch league very much I can't profess expertise on Strootman, but based on youtube footage alone it's not even a close call between Strootman and Fellaini -- go with Strootman. But if he's considered a risk anda Fellaini is admittedly a known quantity in the prem then fine, go with Fellaini. There's something to be said for bringing a player like him late in games when we're down and we need to launch bombs at a massive target like him. But I really hope we don't fall short on Fabregas and have to settle for Fellaini as our "solution" to the midfield problem.
I'm not convinced yet that Cleverley doesn't have what it takes to succeed for United, but there's no harm done whatsoever by having him learn at the feet of the one great midfielders in the game, Cesc Fabregas. I can't still can't believe it's real possibility we could land him...let's see how this plays out.