1- Reevaluate base health.
2- Improve heal support skills, roles, and mechanics as a counter to damage output. And considering this is a team based game, and heal support is a balancing factor to damage, this is logical.
3- Might want to consider raising player limits to something like 7v7 normally for matches to make more possible openings for support roles on teams. And I came from a game that was primarily 8v8, and around that number seemed to work well in pvp.