Yeah, agree with otf about song - it is only "worth the risk" (and you only ever ask "what if") if it was reasonable to begin with. You don't "take the plunge" if it is suicidal - Hleb shoulda known better, and Song too. Actually I think Song is even a clearer example than Hleb (one could imagine Hleb, at that time, making it at Barfa. He had the pass, etc.).
As for Song making it out of Barca - this I do tend to accept: he will probably not fall too much in his level, and a solid DM is useful for most teams. But why lose 2 or 3 years around the peak of your career, and risk it all?
Another thing I didn't see mentioned so far is that Mr. Song took quite a while to actually get to where he was. The jury was out for about 17 years in his case, and he was catching up very slowly, till he made himself Arsenal level. He was not a super star here, and wasn't going to develop into one. Believing that he actually would take a serious amount of wishful thinking (or to believe his lying, deceitful agent).
