Would be really cool if Raid and PvP had spectator mode. It might motivate newer players and would be a nice thing to do during downtime (like while in queue for pvp).
A lot of other games have that and since we already have the spectator mode from floor pov (when you are dead in raid) and the spectator mode that people use to commentate pvp tournaments it could be ez(hopium) to make? That would promote certain content that some players do not have access to i.e: the latest raid, top ranked pvp, inferno raids, etc or have not tried yet.