Probably I'm the only one here who doesn't really like Shumi, having said that, he is the greatest drivers in the 90's till 2006!!! There's simply no doubt about it, winning 7 time world champ (2 in Benetton with Flavio and 5 in Ferrari with Jean Todd), no argument there!
And I don't really think he should come out from retirement, he left a great chapter in F1 history and should just leave it like that, why bother to mess with it again. I'd say probably its desprate times for Ferrari and they need "test drivers" as good as Schumi (no in-season testing this year, so every race is also a testing ground for all the teams), and help Ferrari to test and develop the car for the rest of 2009 and next year (no major aero regulations change).
Now, who will bring back Mika Hakkenen???
(Shumi once said Mika was one of his fearful rival!)
Also will be interesting to see Alonso to fight with Schumi again and also all the new drivers like Hamilton and Vettel.