Mario Gotze would be a fantastic signing, but he wouldn't fill our need in the CM, I think he would have to play in the second striker slot in our unorthodox 4-4-2, which means pushing Rooney up top or switching to a 4231 to get the best out of Gotze.
One has to take into account that over the past few seasons we have not been able to play the same starting 11 for many consecutive games(5) due to form or injuries. This means that positions will always be available and different players and certain opposition teams require operating in flexible formations. There have been games where we've started in 4-4-2 and ended up using 4-5-1 or 4-3-3. Point I am making is we don't really have a set formation and I think whoever comes in can fit in. I also doubt that in his later years Sir Alex will really buy an established aging player. Expect someone young, not well known or "rated", full of potential. This player would be given the opportunity to grow within the team and become the finished article here. (cue Real Madrid to later one want to buy him).
I'd love to have Sneijder but he'd cost too much, it's not going to happen. We're more likely to sign a young, fairly unknown midfielder. Nothing wrong with that if he turns out half as good as Chicharito or Jones. And there's Cleverley who has lots of potential. Everyone keeps saying how our midfield is rubbish but I think we got it covered
I doubt clubs like City or Chelsea will be offering silly money to clubs and other players now that the financial fair play rules will soon be kicking in.