I think one thing that might help the amount of DPS versus tanks and healers, would be to give every DPS a second job which allows them to use that for leveling if they need to, much like how Arcanist has Scholar. I've thought of two, for THM and ARC.

1: Dark Priest. This class would be a callback to the old Thaumaturge of 1.0's release, having an array of skills deal with the astral and umbral. It's main heal would be Sacrifice, which costs some of the caster's MP in exchange for doing a heal that also comes with a regen effect, as well as a buff that allows the tank to heal themselves by dealing damage. The core themes would be using death and pain to sustain the party.

2: Performer. While Bard focuses on playing their instrument to empower the party, the performer takes their art in another direction, using song and dance as the somatic components of healing magic. Based on Dancer of FFXI, this would be a healer that uses TP instead of MP. Their main advantage would be longevity, as TP continuously regenerates throughout battle, although their downside would be that they are less capable of doing heavy healing for a short amount of time (No equivalent of spamming Cure II or Adloquiom)

It's my impression that Pugilist and Lancer would be better off having tanks as their secondaries, which would bring us up to 4 tank options and 4 healer options. While these classes weren't designed to be a healer from the start, and thus lack a low level heal, hopefully folks doing low level content with these make sure to set Cure or Physick so they can aid in the earlier dungeons as well. Also, I'm fully aware the names could stand to be more "FF", possibly finding a job from another game that will fit.