I'm a quad-boxing shaman.

I win WSG by far the most times now, here's what I do.

I join up with a disc priest friend. He runs the flag, I follow him. Getting the flag the first time is easy, on the way back expect resistance. Don't run/kite. Deal with all resistance fast, the first in your dps range dies. Dont wait for them to clog up. You wont move fast. Protect your carrier and time the intercept with the flag carrier on the other side. Drink when possible and train back to your base. Capture the flag.

Rinse and repeat.

It works really well. As long as the flag carrier DOESN'T run away from you. :>