Im not the best experienced person in arena, but a lock refusing to fear is like you refusing to heal. he needs to start fearing, that is an integral part of a lock team, and could probly get you a handfull more wins every week from burning them down while theyre CC'd. I'm also a resto druid (im not fully geared yet, just ~+935 healing, but i didnt want to pass 2 weeks worth of points up to wait untill i was full geared) and as long as my partners do their job we can stay with a winning record for the week fairly easily (and our team isnt a heavy CC team like yours is).
Another thing, im sure you do this in some way or another, but always stay moving and make sure if you end up with a warrior following you around slowing you, make sure that you use natures grasp to gain a little distance then travel form if he catches back up (just rooting or cycloning him would be preferable but sometimes you dont have that much mana to waste or their immune), and if you stop when your out of their LoS keep a close eye on them to make sure they dont come around and surprise you with a CC. When your prowling (if you dont use prowl in the beginning then start using it, not prowling from the start of the game is like painting yourself red and saying "LOOK AT ME, IM A HEALER") always assume their mashing a CC hotkey, so dont try and sneak up on that druid healer behind a pillar, etc.
Also, is your warrior geared at all? 8k HP seems pretty low for a warrior to be comptetitive, from what youve mentioned, it seems almost like your the one carrying the team to wins, which will only take you so far
check out http://www.arenajunkies.com if you didnt already know about it for more info/strategies