Paladins are perfectly fine. If you're not pushing for glad, it's going to be wildly irrelevant under post circumstances which healer you have. Shamans and Priests are currently more represented at high ratings than Paladins, for what it's worth.
describe fine please, 22k flashes with MS up for nearly 22k mana totally fine, sitting in full CCs because u got no mechanincs to get out except bubble(and sac that gets instant dispelled), paladins are the best healers with Cd's, use them and ur dog sh*t, fall behind on healing and ur gonna be oom in first minute, but all of this depends on what level ur planning to play. paladins are very good in cleaves.. so you might consider in playing some KFC(hunt/warr/pala) or TSG(dk/warr/pala), eventho tsg is crap against teams that can spam CC... its to easy to counter, but up to 2k its pretty good.
I want to get into healing for 3s but i dont know if my paladin is currently any good in 3s in this format. What are the ranking for healers currently in 3s with a frost mage?
Resto Shamans and Resto Druids are the superior healers for all brackets in general. Holy Paladin is very viable for some comps tho so you
should be able to have lots of fun while pushing for some rating.