I would put "Don't bother trying this without a good team that knows one another's strengths and weaknesses" on that list, at the top. That more than anything can compensate for the rest; communication especially. There's no way in the universe I'd do a raid with strangers. A lot of people want matchmaking added to the raids but I can almost gurantee those groups would fail unless you happen to get a bunch of Raid pros in one group. And definately use your mics. It is doable without but from experience, even one person (me, being a mute) unable to relay information makes things much harder.