shadowplay (lock,spriest,healer) typically in the bast has been a very strong comp, but spread pressure comps aren't as strong now a days, and with 5.2 turning out to be a season of rogue cleave teams, you will have to be really on your game to beat a decent cleave team. A bette ralternitive would be RLS (rogue, lock, shaman/healer) as the rogue can control a target particularly a cd spamming melee then a spriest.
Shadowplay will be a viable comp. The bane of shadowplay are warrior/shaman/cleave comps, and with warriors getting nerfed we will see their numbers disappear. Sadly no nerf to tremor totem. WLS is currently our best comp but it is getting nerfed through the warrior nerfs and blood fear. LSDv2 will be good. RLS will be good. I can see windwalkers working with warlocks. Windwalker, lock, shaman will be a deadlier version of WLS as their peels are honestly better than warriors. MLS will still be viable.
You're better off going Rogue/Lock/Sham or Rogue/Spriest/Sham, if you can get a hold of a rogue. The problem is that fear, psyfiend, psychic scream, etc all share DR. It might work out, but melee comps are gonna smash you. Warrior/Rogue/Hpal or War/Rogue/Rsham will wreck you, most likely.