I am 95 right now going through Gorgrand and nothing has any spells to steal. is this normal? I have a mod called spell stealer but its not working but that could just be the mod.
It's mostly used as an offensive dispell nowdays in raiding, there are some trash mobs, you can actually steal their buffs from, but generally just dispell. Also not many boss fights use offensive dispelling anymore, hence in raiding for example it's next to useless.
Generally though it's around as useful as slowfall, has some situations where you may use it, but not many.
There is no raid encounter in ToS that makes spell steal valuable.
in mm+ it is ok, and it procs sephuz's secret.
If you play arcane you should avoid using it, because of the heavy mana cost of the spell.
Use it 3 times and you have no more mana.
The mana cost for Arcane is really ridiculous. Blizzard should remove the mana cost and put a 20 second timer on it, or just make the PvP talent Kleptomania baseline.