One other thing to consider is that the general 3s meta is to train healers now, almost no matter what comp you are, and people don't generally mess with locks as they are still pretty hard to bring down. Regarding the sac, don't forget that a large majority of locks were running sac toward the end of last season b/c pets were too hard to keep up. In many ways, this has not changed. Sac also gives you the defensive voidwalker option, and imp dispel. There are situations in which both of these spells are very good. Lastly, we still have port, and have gained the 4 piece to improve it further. Regardless of whether or not you have db or link, port alone makes you insanely hard to land kills on if your team is capable of positioning properly.
Melee teams won't train druid healers, nor will they train disc priests and even holy paladins. Even with soul link and heals double melee still runs me down quite fast, and with fear and cyclone being on the same dr there are generally less ways to deal with melee training me/my druid. Without using SB:Haunt i have a ton of shards for ports/new pets (i just realized they took away SB: Health funnel, rip) and the doomguard root is seriously fucking sexy, not to mention that if you kite melee in the open and use your port behind LoS they're basically taking the brunt of his damage (which is nearly as much as agony in open areas). The only melee i've had trouble with 1v1 is ret paladins, but i think they're just unkillable gods atm.
What i do fucking love however in 2s is using infernal against double melee teams. The aoe stun + aoe damage is amazing, coupled with howl/coil allows for some sick damage windows. I can't say id use one in 3's just yet, but i'm still testing it out. I just dont think GoSac will work against melee cleaves.