In a proper premade vs premade, paladins are only decent during their bubble. You can stretch it to freedom removing roots/slows instantly on someone. outside of that (elemental) shamans are a cause for concern. Coordinating two big dick Windfury warriors plus mortal strike on your own alliance warrior with an elemental shaman burst is probably the worst feeling to have as a healer. And pre-bubbling at a decent health percentage to try and hope somehow that you can top him is actually aids. You also need to consider that a mage can pretty much solo CC all 3 healers on his own if he is worth his salt.
If your warriors cant get back during bubble duration. you're fucked. Not sure why some people are implying slipry is wrong.
There's a lot of fun shit you can do in nostalrius, but trying to take a vanilla private server competitively is the worst mistake you can do. There are a lot of other games that make more sense to take it competitively. But Vanilla wow is definitely not the one.