Nostalrius Begins - Quality wow vanilla realm (1.12)

Hey all, I'm just looking for information on what classes/specs seem to be needed amongst active raid groups. I have the most experience playing a Rogue and a Shadow Priest on retail, but since the former is likely overpopulated and the latter is all but useless in vanilla, I assume I'll need to change it up (but hey, it's probably time I learn something new anyhow).

Any info from players/guilds in need would be very helpful! Thanks ahead!

Resto shaman and warlocks

dwarf

Replace all useless Rogues with Hunters for permanent Tranq Shots on all raid bosses. You only need a Rogue if your raid absolutely cannot clear to Broodlord without disarming suppression traps.

Dwarf priest master class