Most of the problems will be solved after you respec to sub. Also as said above, holy paladin might not be ideal partner for you. Though it doesn't matter that much at 70 lvl.
Anyway, against Dpriest Hunter. I'd first lure hunter to use his scatter shot/silencing shot so you can switch to priest freely. Hunter doesn't really have any other abilities stop your damage if you're sitting on priest. Anyway, after hunter has CD on his scatter shadowstep behind disc, open with 5sec garrote silence followed by gouge and after that have your paladin HoJ the priest so you can save rest of the combo points for damage. Also it's important that your paladin is assisting you with exorcism spam, your damage alone is not enough to kill the priest. Your paladin can pop aura mastery if hunter has silencing shot up to prevent getting interrupted during exo spam.
The priest shouldn't be able to survive damage of you both. If everything goes as planned the priest will trinket or pop pain supression. Repeat until he is out of cooldowns.
Or other way, you could try to go for hunter really hard. It's important that you clear priest of his PS/trinket because I doubt that you can get kill through 'em. Blind the priest, followed by shadow stance sap and then gouge. The priest should either trinket or use pain supression. After that you could do the switch to priest once your Sdance is up again.
Remember to have your paladin freedom you also, if there's freezing(?) trap near the priest when you're switching.
Also as sub it's much more easier to interrupt priest's MC. And also, remember that hunters don't have trap launcher yet(or do they?) meaning that he has to get near paladin if he wants to get him trapped. Now, it's your duty to eat the trap. Try to sprint/step to hunter and run on top of your paladin, if you're lucky it's you who is trapped and your paladin can just cleanse it.
Everything always looks easy on paper....
But anyway you can clearly win them. And best way to learn subtlety is just to play and play. You could play few BGs with your paladin, searching for 2v2 situations where you can train your commination. Though it's not bad to check some high rated rogue videos and AJ forums for some tricks. Though keep in mind that you won't master those tricks in one day.
I hope this helped somehow. If I had more time I'd write more detailed reply.