Haven't watched much of Barca this year but Xavi has seemed a bit aggressive in interviews so I'm not a huge fan. I think Pep is widely liked in the English game unlike Ferguson. I reckon Xavi would get everyone's backs up including our players.
Luis Enrique, another more successful ex Barca manager, is slightly less aggressive but pretty tightly strung so I'd give him a miss too.
Personally I've always liked Alonso, seems an intelligent and calm sort of manager, but maybe it would be difficult for him.