You're probably right Ed, but there are better players ahead of him at Barca and Real, so he would need to take that intermediate step for his own sake.
I haven't read much in this thread, but I think there's fresh talk about him because Milan are reported to not have enough dosh for Ibra, therefore a new deal for Thiago Silva is on the table.
Him or Sakho would certainly add versatility to our defence and moving to 3 at the back would be a more permanent option;
Silva/Sakho
Puyol
Pique
Monster Masch
Abidal
Fontas
and Busquets as back up would be more than enough.
And it's not as if our performance could have done without Keita and the addition of Busquets, it was a very good defensive performance by Sevilla after all and as you fully know, particularly from their last man, Varas.