Why do you think that can not be achieved if you have classes with main roles and certain support skills? Everyone will do their thing as planned, and will assist each other when needed. If Thaumaturge can't keep the mobs in check with CC, LNC can throw in some bind or Voke and grab hate that way, instead of a wipe because all he could do is more DPS. If THM doesn't need help, LNC will keep on DD'ing. If CON is too busy curing the tank, LNC can use bloodbath/chakra and regain his HP that way, without having to wait for CON to cure him.