Reworking frontline from the ground up, starting with getting rid of the three team BS (my ideal would be two teams of 12), and making them less rng based, it's not fun to have a good team but lose because to spawns are on the enemy doorstep.

Fixing whatever the heck causes ability delay.

Diminishing returns on cc, three WHMs just imp you? Oops they just gave you cc immunity for x amount of seconds.

Get rid of all one shot gimmicks.

Get rid of the ridiculous damage reduction for melee, it shouldn't take an entire frikking party (or more) focusing to kill ONE melee.

That's all I can think of off the top of my head for the moment.