I've read a lot of the views in this thread, and it's most interesting to see both sides.
Here's my take on the whole thing.
Rooney left at a time when the club desperately needed the money, and he needed to move because he was not going to achieve his full potential given the squad around him at the time (and, as it transpires, the future squads here).
Professionally, he gave it his all for many years, winning trophies and setting a goalscoring record which will probably never be equalled there.
The downward spiral for him came, I believe, in that last season of Ferguson's, when suddenly he was dropped and everything was uncertain. Ferguson sticking the knife in for his previous wage revolt? I think so.
Since then he has not been the same player. I have suspected that his heart went out of that club, and his performances suffered as a result.
I think he wants out, and the only Prem club he said he would go to was us. Fine.
What would he bring to the club?
I believe first of all, Koeman would get him on a training regime that would get him fully fit again (something that the Mancs appeared not to do).
I believe he would be re-invigorated being here. He would be wanting to play again - busting a gut whenever he was on the pitch.
I believe on the pitch, he would be the 'captain' even if he did not have the armband - HE would be the one geeing the rest up, not letting them get slipshod in what they do, driving the team on, getting the crowd to get behind the team.
Off the pitch, I believe his great experience and know-how would work wonders with the young players in the team - I cannot believe he would simply join us and then do nothing to bring on the younger players for the benefit of the club. I bellieve he would relish the 'senior' role.
He's made his money off the Mancs, and if he has invested/saved it wisely, he should have no financial worries for the rest of his life. He should be able to come here on reasonable terms.
Overall, I believe the benefits outweigh the potential disadvantages of his age, and his not being quite fit at present.
Now, over to the rest of y'all...