Playing a Melee DPS is suicide. Not only because all the Mechs have mid range attacks (wich hit almost every time even if you run out the first second you see it) but also because everybody and his Mom focus you.

Healers are Gods. The know it. So they go out alone, seeking 1v3's and spamming emotes while 3 people are not able to kill them wich leads to no Heal in the bigger Fights. The Picture in the end looks like this: all DPS are dead, Healers are spread around the entire map, being the only ones alive while running from /fighting 2-4 people.

Those are only 2 Problems of a bunch and im Sure SE is aware of them. Its probably time to implement specific Nerfs Again only for large scale PvP. (Like they did with potencys and stuff in 3.X)

Healers Attacks should have a Cooldown. Its just to OP being able to survive 3 People and even kill them after a while or, remove the potency completely and make them CC only (slow, root). This way, Healers would focus on healing again. They will still be immortal in 1v1 though...

For MeleeDPS i have no idea how to fix it. Maybe they need bigger potencys to even out the handicap of being the ones who get hit by everything. But at the moment, the worst you can do for yourself and the Team, is playing a Monk, DRG etc.