If you have four priests, I'd think you'd make a larger impact on the battle healing the swarm than killing with them.
Almost all of the losses (as Alliance) is to horde who turn the game into a grindfest by turtling near the Iceblood Graveyard.

If the sides race towards the generals, the alliance wins most of these.

As a DPS spec, you can cap bunkers/towers and backcap your own.
Belinda is much easier than Galv, so once you have some gear you should be able to solo her if she's up.