I agree he belongs in Serie A....and no where else.
I don't think there was going to be a better enviroment for him than the one he had in Madrid, his fav coach being the coach there, sorrounded by top class players from Zidane to Ronaldo to Figo and Carlos still it didn't help him.
Yes, if he's sorrounded by the right people, right enviroment everything he needs he could become one hell of a player, but we can't gamble can we? specially looking at this delicate situation we're in. the last thing we would need now is Cassano crying. seriously.
As for Diego, you're right he's a bit expensive comparing to Cassano but he's worth it, he's such a talent and classy player.