Xisco, Ranger or Best would never have been in position to miss them.
How can anyone predict Xisco's quality? He's had literally minutes against Villa and that's it.
So far he's the only one of our strikers who hasn't had a chance, on that basis alone he deserves it.
As I said, I've seen a few matches of him during his Santander spell, and he really does not look bad. I honestly believe, based on what I've seen, that he's the second best striker at the club. He's not a great finisher, but makes up for it in team play, which is pretty much what we need to keep feeding Carroll. Loven had (IIRC) two shots that he should've placed to a better positioned Carroll rather than fire at the target, Xisco (again, based on the matches I've seen), would most likely not have gone for glory.
All this said, though. You do get a lot of more time on the ball in Spain, and he's not played enough Prem football to have a decent comparison. But still, he deserves a chance to prove himself.