To help players out, there should be a "reward" like system for doing the task your current class/hero is most suited for. For example, when a Heavy or Hybrid (depending on the hero) boosts a zone, they should get +2 renown instead of +1. This would tell the player "Hey, you should be doing this with this class." Assassin type classes I guess would be considered flankers. They'd get a boost in renown for shutting down players. Hybrids well, seems to be a mix bag depending on the warrior. So I guess a Lawbringer would have different priorities then say a Valkyrie. Vanguards would be your basic damage dealer. They'd get a boost in renown for killing minions and helping defend teammates.
My suggestion might not be perfect, but it's a start.