I have two war hero toons, and sadly one is a BH merc. When the new game began a few months back, it was unclear to me the relative value of each class with regards to pvp. I rolled a BH as my alt because I liked the armor models and it's fun to blow stuff up. However, Merc BHs are possibly the worst class in 1v1 pvp, as they lack strong defense and they are too easy to shut down. Their weaknesses are not always apparent in group play because if postioned well they can appear strong if left alone.
I guess I should have abandoned the BH toon a long time ago since I do enjoy pvp, but I still like the armor models and its kind of fun playing an underdog class against other players. I have to admit that I chuckle each time someone loses to me 1v1. Against decent players, frankly I don't stand a chance unless I can use the terrain to my advantage. Sometimes, I get lucky. IMO BW should give mercs a little bit better defense to balance them better.
In the meantime, I wish I could change over to PT-pyro w/o having to re-roll.