One - Surv is same strength if not better than BM on singletarget.
Two - there's no fights this tier that benefits BM more than Surv. Jin rokh's pools lines up badly with BM's burst, and every single other fight favors AOE/Multidotting *heavily*.
Also, GL using the rep trinket with my levels of hit and expertise. So many wasted stats.
As for Barrage, so far found it a dps increase on Horridon, Council of Elders (assuming you hit all 4), Tortos and Magaera.
BM is imho fairly superior than SV for single target if you dont hace rppm trinkets and if you are lucky with thunderhawks. Yesterday on durumu the other hunter pulled 10k dps more than me, he was bm and i sv. One of the reasons is that my thunderhawks did 1,5 M dmg and his 4,1 M.