lsfreak wrote:
Against your own level, there is a 4% base miss chance based on level.
Indeed. If all you fight is equal level mobs, the talent Elemental Precision will completely +hit cap you. As you're leveling, you will need a bit more if you fight things higher level(I know I did).
It is definitely a good idea to reach the +hit cap when raiding. Nothing is more annoying than not doing damage on that hit.
lsfreak wrote:
EDIT: Also, I may be mistaken, but I think almost any resistances that bosses have are almost entirely negated by Curse of Shadows/Curse of Elements. Provided they're up, I don't think you'll need spell penetration.
Bolded the important parts. If you're raiding without a warlock(not uncommon in Kara), then a bit certainly won't hurt you. If you're raiding with a warlock, picking up a little here and there can't hurt, but I wouldn't worry about it too much.
My rule of thumb is to have both Arcane Subtlety and a Spell Penetration enchant to your cloak(not like you have many other caster choices there). Then you won't be gimping other stats, but will have enough to get by.