Exploit #1 - Leaving so soon?
Mind Controlling an enemy out of an instance portal in Warsong Glutch removes them from the instance. This is fairly simple, and extremely annoying, it is easy to avoid however, unless the opponent has the flag and are waiting by an exit portal.
Exploit #2 - Hide and seek
Can't find the flag in Warsong? Lucky you, just stand near the middle of the instance, load up the score sheet, and manually /target *enemy* and Mind Vision, the only people you cannot find like this are Rogues while stealthed, however, stealthing removes the flag from you, so nothing is lost.
Exploit #3 - Kazzar? More like !&$% You Raid Group!
Kazzar, the elite humaniod mob that is summonable in Alterac Valley is Mind Controllable, however, this leads to something intresting. When you Mind Control him, it resets his tap to you, hence, if an entire raid group is killing him, just Mind Control him, and you get Kazzar without anyone else getting your dirty loot (this is, by far, the most annoying of the exploits imo, however, it might be only done with Mind Control cap, as it's untested by me)
Exploit #4 - Higher DPS than an anything
You know the vendor that sells stuff outside Alterac entrances? He's level 58, is as powerful as a BOSS, and can be Mind Controlled. Simple stay behind the vendor stands in front of, Mind Control him, and watch as your DPS goes to the 500+ range. No !&$%ing joke. These guys hit as hard as bosses, make sure to use the Strike (+300 something damage I believe) and cleave (+something damage and hits more than one target for a regular hit, making it an instant AoE 800 damage or something around there) the best part? These moves have very little cooldown, and these guys hit for 400 damage and attack at once every .75 seconds. If Mind Control breaks, simply run away, these guards NEVER catch up to you.