Just to play devil's advocate briefly--- BA will actually do about 30-40% more damage than a vulnerability boosted AS if the minion it summons has 100% uptime (not guaranteed, I know). Testing on a target dummy with a fresh character on the pvp realm, vuln+AS was about 145k damage, BA was about 135k from the DoT and 65k from the summoned minion melee attacks. That being said, the dispel issue is real and I'd probably pick LnL as well if only for the easier sting application.
The only other thing I would add is that LnL should be taken when you are not playing with a Spriest or Lock. Without dispel protection BA is meh, decent healers will dispel on CD and since it doesn't have the old reset on dispel mechanic or anything else attached to it like the old LnL it just isn't that good. It does the damage of a Vuln boosted AS.
Also, haven't had a chance to play any games as MM yet, is it viable to take viper sting and just train a healer? I know Glink had mentioned in his BM video that it was viable with that spec. The combination of MS+viper sting is roughly like 50% less healing on the healer... it just seems like if you play with a high pressure melee you'd just be able to turn a healer's butthole into putty with just moderate control on the dps.