I have found BH to be a bit slower than some other classes. I am leveling Merc in the arsenal tree as well. Thorsblood I am on Harbringer, currently lvl. 19 and finishing up with Balmorra.

I can say that I noticed a hit in perfomance after the Maint. on the 5th of Sept. In full disclosure my PC is from the early 2007 era using an old AMD 2600 @ 1.2 Ghz I believe?,and a cheap Nvidia 9500GT GPU. I have Win7 x64 and 8GB DDR2. I know this is not ideal for any game but to be honest I was not expecting much when I installed SWtoR on this old rig but I played WoW with about a 35fps rate with little issue. I could not do 25man raids but 10man were manageable. When i first started SWtoR about two weeks ago the framerate was decent and I did not see any issues in the low level FP's but after Wednesday I have started playing on my laptop which is much newer with a core i5 CPU, low end Nvidia 525 mobile GPU and 8GB DDR3 as even solo questing is terrible after last Wednesday on my vintage desktop.