Touched by the Light.
So Touched by the Light increases SP...as a Tank?
How does SP affect me as a tank, and should I spec out of it?
No, you shouldn't spec out of it. While our main threat moves are independed of SP, instead scaling with strength, AP, and BV, much of our threat still comes from SP.
Touched by the Light is a lot of threat for the talent points it costs. It is definitely a good talent to take (I consider it a must). We do scale better with the other stats, so you shouldn't be wearing spell power gear, but the talent still is a decent threat boost none the less.
It makes me a feel good that I get about 9 Spell Power for every 24 stam gem I plonk in my armor.
It's the 2nd best threat per point talent available to us. Don't drop it.