I have been frequently playing Frontline since 6.1, and surprising nobody, I have some thoughts on job balance and possible reworks. Let me know what you think.
DRK
DRK's method of dealing damage via Shadowbringer, dropping its own HP by 12000 for 6000 potency, is not rewarding enough to justify the risk associated with its use. A temporary, non-stacking shield equal to the HP lost would be helpful in keeping it alive without fully eliminating the risk involved with spamming Shadowbringer out to burst damage quickly.
GNB
GNB faces a great many issues, but I will address some of the more glaring ones.
Draw and Junction being dependent on which enemies are available causes frustration. For example, if an enemy party does not have a tank, Junction Tank is made completely unavailable to you, and you lose the ability to utilize Nebula and the shielding offered with Continuation. If you're already holding onto an ideal Junction, you could be forced to forego the extra Powder Barrel proc offered by Draw and Junction in order to have the right Junction for the situation. This sort of compromise is not fun or engaging, and I would much prefer that Draw and Junction be usable in some other fashion, perhaps by drawing from teammates or as a toggle without a target.
GNB should have crowd control immunity during the channeling of Relentless Rush. It is already a risky LB to use, requiring that you remain in melee range of your targets and becoming effectively useless if crowd control is used on you, but this is made worse by an inability to cancel the LB to use Recuperate or Purify should a Stun or Miracle of Nature be applied. If WAR can have crowd control immunity during its 15s of Inner Release, it would not be unreasonable to lend the same sort of effect to the 4s of Relentless Rush.
Junction Healer's Continuation effect is a scant 10y in radius, which will have severely limited effect in teamfights by generating no healing for anyone who isn't immediately next to you. An increase in the heal's range would be welcome, along with a small increase in its healing potency such that it makes more of a difference and causes Junction Healer to be a more attractive buff as a result.
WHM
Miracle of Nature is too strong as an uncleansable 2s silence every 25s, able to shut down pushes and cause secured kills on its own. A reduction in its duration or an increase in its cooldown is necessary.
With Afflatus Purgation being an exceptionally strong LB, it should have its generation speed or its damage decreased. A 40y LB with 18000 potency in damage, a stun, a buff, and healing should not be available so frequently.