Originally Posted by Endahl

There should be no cost to bringing a shadow priest as part of your Anub 10 healing strat whatsoever. If you find a shadow priest gimping your raid or doing anything other than eliminating the need for Leeching Swarm heals for their group (whether they have Imp VE shouldn't really matter), the problem is the player and not the spec.

As for your other question, a ToC 10 geared (232/245) shadow priest should do more than 4k dps on a heroic target dummy with self buffs alone. Actual raid DPS will vary a lot more in 10-mans than 25s due to variance in buff availability, but it should be higher than 4k for both Beasts and Jaraxxus due to all the multidotting even if there are no spell damage buffs in your raid whatsoever.