Class roles in Velious?

[Mindsplatter]

Looking to start a new main character, I don't really do the alt thing, so I'm planning for the long term. I'm looking for a class that's relatively fun and as complex as possible to play on raids, desireable for end game content, and preferably a decent soloer. Considering the following: Shaman, cleric, druid, necromancer, monk, enchanter, warrior. Could anyone outline their roles in Velious raiding? My main motive is raiding, so I want to enjoy my raiding experience (feel like I'm serving a unique role, not just button mashing)