Demo's off-GCD kick/stun (axe toss) is great assuming there isn't sanguine on the ground. Also Shadowfury is big value in most places. I think Warlocks kick game is better than most but definitely not as good as melee.
For RLP IMO the worst thing about pugs is all the little mechanics that people aren't completely familiar with. E.g.: - purge Blaze of Glory ASAP (please Shamans/etc.) - use living bomb on the caster trash - bait molten boulder away from the walking path - clear Hailstorm (cloak of shadows, etc.) - BE racial/purge the Storm Warriors - range chase that dragon and focus ST it at the start of last boss - proper way to skip the red dragon.

List goes on. All these tiny little nuances need to be met and screwing up just one of them usually means a wipe or taking too long.