I have to admit I am not too keen on the idea but I think the OP is trying to broach a subject that many reject and probably didn't try to lay it out in a well thought out way that conveyed his whole idea. What I took from this after reading three pages is it is a bad idea because of lack of comp, chat/voice coordination, and of course the scourge of BOTs.
If I understand the OP correctly it would try to match people based on Skill (ground up MMR/CR based on winning from previous solo-queued events), iLevel for Gear, and potentially roles. So a standard RBG has tank (prot war/pally, blood DK, guardian druid, brewmaster monk), 3 heals (any combination of these Resto shaman/druid, priest (disc/holy), holydin, mistweaver), 6 DPS (you could group 3 melee (fany combination of these eral druid, windwalker monk, rogue, arms/fury warrior, frost/unholy DK, enhancement shaman and retadin) in melee slots and then 3 ranged (any combination of these mage, hunter, ele shaman, boomkin, lock, SPriest)). Just lock queued spec's so they have to take the queue and stay in that spec... you change spec you get dropped from queue. You zone in and the preparation doesn't allow a swap.
Worse come to worst it is a chance to practice RBGs/Arena CRZ. Just build in some functionalities to boot bots and have that lead to some harsh treatment of those accounts after they are investigated. I don't like dumbing down content but make it like a random Wargame maybe so people can practice but not profit from easier/less skilled content. Could also be a good way to blow off steam after a guild RBG SNAFU or if you only have 20-30 minutes of gaming time and want to practice you skills.