I run a Pally Tank/Mage/Mage/Rogue/Shaman Healer group right now without a single /click macro. My DPS is on par with equally geared players in 10 and 25 man raids, my threat generation is fine on my pally, and I've got no problems finishing any heroic dungeons except for the ones requiring vehicles (I'm confident I could beat them, I'm just lazy.)

The only thing I can see ending multiboxing is removal of /follow OR making it against TOS.