Cloth Itemization in Cataclysm
Yes. If it has +hit on it, it might be attractive to a mage, lock or Shadow priest. If it has +Spirit on it, it will be more attractive to healing priests. If it has neither stat on it, then it might be attractive to any cloth wearer. (
Source)
Spirit in Cataclysm
You'll need enough Spirit to have good regen. That probably doesn't mean you're going to pass on every item without Spirit.
Spirit is a weird stat that is technically primary but has more in common with stats like crit and haste. What I mean is that if you found an item without Intellect, you'd almost certainly pass on it because that likely means the item has Agi or Strength instead. But if you find an item with Int but no Spirit, it might be a good upgrade. (
Source)