It really should be Reborn mage, Necromancer, 133 shade, forgotten mage, dragon. Hood-disablers are terrible and will cause you quite a lot of food if you don't kill them ASAP.
No way should dragons be a high priority; they only attack one player, and their damage can be almost entirely blocked by praying mage. On top of that, they have HUGE defense; the time you spend killing them you could usually have cleared every other monster in the room. Shades should be first; they outhit any other monster, can't be blocked with prayer, and have much less defense than hood-dispelers.
Not entirely correct, the Shades can be half-blocked, and flashing between deflect range and soul split allows a single player to barely kill a 133 shade without food if no other monsters interfere. Still, they do a ton of damage over time.
I'm going to have to place the Shade under the Necros because the summoning tendency of high level necros can spawn insanely highly damaging skeletons.
Also, dehooding monsters are irrelevant if you don't use a hood.
Also, because the Soulgazer hits all players at once, as opposed to only one at a time, its priority should be raised.