Remanz is sorta right.

Warriors

Warriors have a lot of problems but their burst is absolutely fucking retarded. A single warrior if left to reck + bladestorm + pop trinkets will do more than 50% of someone's HP.

Catching up to your targets who have run speed boosts isn't as difficult as its been pointed out, you can abuse the larger range of Piercing howl for AOE slow at 10 yards. Heroic leap is usable while boxing if you can set the camera angles and make buttons to go to those angles when you are about to do it... keep in mind though that your slaves will be a few feet behind your main when you do it because they won't be 100% stacked on the move. Another thing about warriors is that they are sitting ducks for mages... if you do not get a 4-5 on 3 then game should be over if they have any mages. Their damage increases over time as well which can make them do some huge numbers... and that "one shot" macro will kill someone no matter what.

Rets

Simply put you do not want 4 rets... you want 3 and either a DK or a rogue. Main reason being... you have NO slows whatsoever. Their wings are easily spell stolen so you better kill someone FAST if theres a mage on the opposing team. They rely heavily on procs and that is very hard to coordinate (though not impossible). On the plus side every 10 seconds you can save a teammate from dying (healer or 4th dps) and you have loads of utility. You are a one trick pony though and as soon as bubble and wings are used you are a sitting duck as they have very little sustained damage.

My opinion
Only play 5 in bgs. Level and gear either warriors + rets or dks + rets. Lead from the ret, grab yourself a disc priest or resto shaman healer and do 3's.

I'm sitting around 2100 on my quad dk team... its much harder now that the hungering cold nerf went through.

I personally am leveling shammies, warriors and rets because i like the challenge...plus the damage output of all three are retarded during a burst phase. Of the three teams you are best off running a dk team if you want to have the least stress possible. I do not think dk + 4 rets is the only way to go... dks require almost zero interaction once you set them up correctly the only thing i do is have set focus and then they are good to go for timed silences etc etc... so you CAN heal yourself (i did it to 1900) but it is not recommended.