My buddy has an ele sham at 85, stacked mastery and wearing almost every BiS peice, hes very squishy.. they do excellent AoE dps with chain lightning spam, you get procs on top of procs with it. He averages 60k single target, with 90% mastery
I have a shammy with bis int gear and found that ele is just too weak for bgs. it takes too long to build up some burst before you get trolled by almost every other class that can kill you way before you can get them down. IMO ele never really scaled past the 80-84 bracket, if you want to make a ele twink stick to that bracket as its ridiculous. You are better off going enhance if you cant stand to heal at 85. resto on the other hand is very good.