It gets better, I'm a 50 merc and am nearly on the top dps chart every game. While yes you are basically a turret, and have to act as one, you are a force to be reckoned with if you have a healer and decent armor. While tracer missile -> heartseeker - railshot should be your single target burndown, don't be afraid to let fusion missile, explosive dart, and death from above loose on groups of enemies crowded around a single opponent, this is where a vast majority of your damage will come from, and because you are hitting multiple targets for vast amount of damage a single healer can't cope with all of it. While if you get dogpiled, yes you will die, with explosive dart and aoe abilities you can make them pay somewhat for killing you. One of my favorite things to do is to aoe blast them back, shoot explosive dart and then fusion missle. It will take a large chunk of their health as they close back in. So, in summary, yes it does get better as a BH, all lower level classes will get very quickly destroyed until they separate the brackets, as I can basically target a player in their teens and burn down within five seconds of pure damage.