I'm going to keep playing Arms Warrior + Resto Shaman + Holy Pally with 2 really good friends of mine. It has been my favourite 3v3 setup since I started playing WoW in season 3, and I've tried it out every season. Was my main setup in season 3, 7 and 8. It was never very good in WotLK, though. We were the top team on our BG with the setup for a while (not counting those that ran with ele shammys) at ~2300 team rating. Really looking forward to Cata as it seems like this setup once again will be somewhat good. Resto Shaman and Holy Paladin both bring awesome support to me as a Warrior, and they are able to dispel CC from each other now that Shaman can dispel magic.
It seems like the slower pace of cata also will fit the Resto Shaman's and my playstyles very well. I usually outdamage other warriors by lots (though, I'm not very good at using my CC offensively, I tend to use it defensively to keep my team alive in a tricky situation. So, that dmg didn't always lead to a kill in WotLK), and the resto shaman I play with is insane at mana management (seriously, I don't think I've ever seen him go oom in 3v3... played with him since start of wotlk). As it seems atm, Cata arena will be a lot more about heavy pressure and mana than in WotLK (and less about blowing someone up in a single CC), kinda like it was back in TBC, and I'm really looking forward to that.