Hey,
Warzones are simple... stay with the pack. I like to hover around and not really get noticed while taunting and guarding on every possible CD. I always use awe when its up on there pack as it can give your team time.
In open world pvp, I had similar issues to you. Mainly because guardians really do need the gear to perform well. However I found that taking out there healer while stunning them worked well. You would end up fighting the imp with doc healing you.
Often they will get the jump on you and hammer you companion. I liked force pushing them away and running the opposite way... Get out of range and combat. Then simply dismiss dead doc and then re-summon him back at full hp:)