I'm not suggesting it's outlandish, far from it it's just that the very best midfielders in the world are at your Real Madrid's, Barcelona's at the like. It's just my opinion that from what I've seen Modric is the best from the rest, he's certainly the best midfielder outside of the Sky 4 & City in the premiership.
Again by all means name names, it's all very easy to say there's better options than Modric but it seems a lot harder to actually name them. Sneijder seems to be the one everyone keeps mentioning but I have my doubts if there's any real interest from United in him, if there were I would have expected him to have been signed years ago tbh.
Real Madrid don't have great central mid's, Khedira is a joke, Diarra is very very good but seemingly wants out, so thats a Real one thats available, anyone that can be remotely objective would also see Alonso was pretty rubbish for them in the majority of games.
The main issue is, Carrick, Fletcher, Anderson are pretty rubbish, you don't need to buy the "best" central midfielder in the world to have a huge improvement in the Utd midfield. I don't really rate Nasri, but he's FAR better than Anderson, or Carrick. Parker would be short term but is again better than anything you have defensively/combative. Diarra would be pretty much perfect, he's not only defensive, though he can be, he's very good at passing and driving a game forwards, turning defence into attack.
The thing is, no one can really state definitively what Fergie is looking for, is he going to play Young in the middle, his passing, movement, vision, defensive workrate are all a cut above the three main guys you have now.
Do you need a better defensive midfielder to play with Young, or are you going to play Young and Nani first team and Valencia only as rotation/cover, and you really do need a creative midfielder.
I still think central midfield, at least for this year, is the lowest priority, they can be improved upon, easily, but, you don't have to have the best player in every position to win the league.