And yet #1 ranked guild in the world is using (and used during progress) all of those (although resto druid only occasionally if 3 healing) when they all have alts to switch?
Sounds strange to me.
It's hard to put classes to any particular order when it depends so much on the encounter but this is my 10 cents regarding 10man:
Worst healer: Resto Shaman
Worst Tank: At start it was warrior but now with better gear warrior works much better so I say monk.
Worst DPS: This is hardest due to encounter mechanics but I say MM hunter