Kostur
海尔的老板
He won´t.
I think the position that is often neglected in this debate is the one of the player itself. Let´s assume, that Dortmund would be willing in letting him go for 60+ Mil. €, why would Reus join United this Summer?
Your club will undergo a pretty big rebuilding phase this Summer under a new manager, which results in a considerable uncertainty that United will offer him more title chances than Dortmund (which seems to be his main focus in choosing a club). You won´t play CL next season.
Reus´ best choice of action would be staying at Dortmund as the undisputed star player (especially in the eye of the international audience) for another year and then transfer for a bargain (in relation to his standing) in 2015. If Reus at least keeps his performance level then nearly every European elite club will line up for him. Clubs who will be willing to spend more than 35 Mil. € for him. Everything on top of that figure will go directly into his own pockets and the ones of his agents.
Naturally, I just think of the reasons why your club won't let him go first and foremost because that's probably the biggest obstacle to overcome. You simply can't 'afford' to lose him now.
You're right in that he's been their best player this season, has become frighteningly productive and selling him would seem a bit mental with their main striker leaving too.
It's a tough one to judge though. I suppose the situation is very different when there's a release clause at the end rather than a Bosman. But a few years down the line they'd probably regret not cashing in on an extra wedge from Reus on top of a big fee they wavered for Lewandowski.
The fact he worked a release clause into the deal and the club were willing does suggest that he's given a potential move a lot of thought.
I think that they'll try to force him this year to sign a new contract where there will be no release clause ( he's the last player in their squad with such clause iirc, maybe @Sphaero can confirm ) and if he'll be stubborn enough not to sign it, then it will be release clause / bidding war next summer I guess.