With quite a few of the talents in all classes, there seems to be a mantra for Lich King to combine this and combine that. Dual purpose or dual effect talents. With the latest few builds it seems like they are adding-removing, reducing-improving such talents in order to crunch numbers.
As for the priest class, here are a few I would combine.
1: Combine Fortitude and Divine Spirit into one buff and place Imp DS into the Holy tree.
2:Combine Vampiric Embrace and Vampiric Touch, make it a 51 pt. talent. Put Dispersion up were Imp. Psychic Scream was, because it is now part of Horror.
3: Combine Lightwell and Circle of Healing, Circle goes first...leaves a well. Only one Well up at a time.
4: Combine Imp.Power Word Shield and Reflective Shield.
That about does it, any holes or gaps left in the trees can be filled up with the " ones that didn't make it".
Now get back to your desk and crunch those numbers and I'll see you on Nov 5th.
Thank you and have a pleasant evening.