Alright, some good feedback here. Gonna put up a wall of text with more recent thoughts :P

Making certain skills cross-classable would indeed be outside the current design, so there would have to be some changes
to get it fit the current design. Additionally, it seems that not having CNJ seems to be a thematic conflict, so I'd be willing to put it in,
however, I do also realize that many abilties are more BLM inspired than WHM inspired, meaning it might be a good
option to replace THM with CNJ, rather than replacing ACN. Considering I gave dualcast already some swiftcast-like behaviour, adjusting it
a bit would allow for missing swiftcast. With cleric/protect we no longer need to have combat stance/ward, so we can bring in
2 more skills. Further, blizzard 2 would be useless anyway due to this job's AoE abilities.

The 2 new abilities would have to fill the gaps that are filled by the extra cross-class abilities at this point:
Instant ranged attack (they do get one with aero, but a plain damage attack would be welcome)
Ranged ST heavy
A potent DoT spell.

So I propose this:
Spark: 100 potency damage, instant cast.
Banish: 30 potency DoT for 21s, 40% Heavy, 2.5s cast.

It adds a bit more elemental variety and an ability that would be considered white magic.

Additionally, swapping out Combat Stance for Cleric, would mean losing 10% speed and gaining 10% damage, I'd not like to
change this, so I'd put the speed buff on Enfire instead. Doing this would be a slight buff to healing overall.

Further, to consider the combo potencies.. I did not actually notice that pattern, but I think that the important
part is to balance the total potency per gcd of the entire combo, rather than just the finisher. I did not calculate it through, as it'd be a lot of work.
I actually just did a bit of it, and decided it was way too much work. Things need to be balanced, but also potential complexities that come with the nature of
melee DPS, like auto-attack timings/potency, and how tooltips will be interpreted by the general playerbase is something that makes potency balancing not an easy job.

On the topic of Enfire mechanics..it's inspired by Astral Fire and Blood of the Dragon,
I like the idea of treating time on a buff as a resource, and by making it easy to apply like Astral Fire, it's not as punishing as BotD.

The desired rotation at level 50 involves getting enfire up, putting up DoTs, and fill with Flame 2.
At level 60 it involves filling with Flame Slash combo instead and using Flame 3 to cash out some excess Enfire duration.
Flame 2 would be used if you have to stay at range, or to more quickly build up Enfire duration.

Involving healing in this, I think the way Enliven works atm might be a bit annoying, and would encourage players to keep the regen on the tank between pulls, so I'd take away the Enfire consumption of that. Instead I'll put that consumption mechanic on the shields the job can provide.