Originally Posted by Fat Hugin
I don't play Sun, but...no Rapid Spin? Yes, Magic Bounce helps, but you won't be perfect with it, and many Rockers can OHKO Xatu, so you can't constantly switch him in.
It's certainly an option, but I find that Xatu beats the vast majority of rock setters. Xatu can stand up to all the defensive setters (Ferry, Forry, Skarm, etc) and has some interesting tricks against some of the offensive ones. For instance, Tyranitar hoping to set up rocks gets promptly U-Turned into Dugtrio who proceeds to smash him. Terrakion also meets a similar fate, although the outcomes may vary (pending choice sets).
In a perfect world, the team would have Xatu plus an emergency spinner, but finding room for such a thing is extremely difficult. Sun already dedicates half its team slots to necessities and near-staples. Starmie makes for an interesting choice for a situation like this, because she can both spin and function as a niche revenge killer with Bolt/Beam/Spin/Trick (awkward yet potentially useful set).
One possible exception would be if you're using Ninetales on a (...wait for it...) defensive sun team. This is a whole other can of worms though and its viability is rightfully scrutinized.