The rumour circuit says Busquets has pubalgia and they went through the "conservative care" thing last year (rests between games + physio), followed by a longer rest this summer, but it hasn't worked. If that's true then he won't get better without surgery and a few months out. Just a rumour for now, but it fits that vaguely under-powered look he's had for a while.
Pique is still alleged to be enjoying his poker, celebrity (and married) life too much. He did shine in a great team with Puyol reminding him of his job, but he was a top defender for a while. Whether he can be again is anybody's guess.
As for Enrique, I just don't know. He was supposed to have a plan and strong opinions, but his team selections might as well be generated by a pinball machine.