Paladin: Fighting a paladin can be very easy if you are good at frost kiting. They have no long range attacks and no abilities to help them get Rose zuly into range like intercept.
You can treat them like a warrior by keeping as much distance as possible and always having a chill effect up. Your main concern when fighting a paladin is making sure they do not heal.
If you do not do anything to stop it you will run out of mana long before they run out of health. If you see light forming around their hands they are trying to cast a heal. It can be tricky because in PVP good paladins use the quick cast Flash of Light spell to heal.
If you time it right though you should be able to use Counter-spell to shut down their healing, when this happens crank up your DPS, but do not go all out. You will not be bringing them down in this phase. Your increased DPS is intended to make them panic and use one of their bubble shields to save themselves.
Once they have used it wait ten to thirteen seconds before cranking up your DPS again. This will give you time for your Counter-spells cool-down to finish and it will be ready the second time they try to heal themselves back up. This time when you use it they will not be able to use a shield and you can blast them down.