I basically decided to focus on the sentry role because keeping the bank clear is typically not a priority for a lot of random players. One of the issues affecting player behavior is the idiotic leader board. For the less experienced player they will look at it and think the only thing that matters is number of kills, motes deposited and guardian kills. This means many will simply avoid taking in powerful enemies (elites and blockers) ... while chasing every mote. I really wish they would look at it and either remove it or redesign it based on the effectiveness of team roles.