I belive that you can box anything in bgs fine as long as the enemy team is a full pug. It does happen when you queue with more then one that you meet pretty good geared 3v3 teams etc and they tend to own me even with 4 well geared shamans. The lack of a private healer is so obviouse when a ret paladin + warrior focus you, if the warrior blow aoe fear in my chain heal im most likley dead.