yes, big big emphasis on competent groups members.
altho, i have heard of a "wizard cleave" team in 3's recently. basically its destro lock, elemental shammy and heal pally. between grounding totem, hand of sacrifce and cleanse you have a lot of anti-CC, which can be supplemented by a fel hunter if need be. the warlock brings good all-around control in the form of the aoe stun and fears, as well as a succubus if the lock opts for that instead of the felpuppy, while the elemental shammy provides anti-melee with the earthbind root. both casters are high priority targets; you cant let either one of them free cast or something pops. but the presence of the holy pally, with that new anti-interruption ability of theirs means theres a ten second period where nothing short of outright stuns or very well-executed CC can stop the shammy and lock from nuking. of course, the pally has the counter to that with cleanse + bubble, and the addition of heroism is just gravy.
ive heard of highly skilled RMP beating this comp, but at the same time ive heard that the margin for error is miniscule; if the rogue screws up a CD, or the mage gets caught on a GCD when he needs to ice block, or the priest gets too far away from some LoS, somebody on that RMP team is dying. its even a very strong anti-cleave combo, due to the earthbind root, HoP and aoe CC via shadowfury, howl and thunder. the nerf to prot healing will hurt this a bit, but straight holy still does a nice job. but as it stands now, getting a prothealadin in with this comp would be brutal; 20s hammer with an on-demand high-damage silence, plus insane staying power = sexy beyond belief.