I would also like to see CNJ get a dps role. Given the background of the CNJ class quests, geomancer would make sense, but if the lore about white magic becoming forbidden is all correct, then some other kind of Cure/Holy/Light focused dps class would also make sense.

There is however a problem with certain classes getting jobs of different roles, CNJ is one of these. Unless job crystals can reduce stats (and so far as I have seen no job decreases any stat), then any CNJ job will have a fat stack of mind at lv50 even if they are limited to casting (int) gear. Further, the effects of abilities from your base class can be changed to some extent based on your job, but unless they did this to a significant extent, at level 50 you would have cure, cure II, medica, medica II, esuna, stoneskin+trait, and raise+trait, which is a huge arsenal of healing abilities. What I'm trying to say is that without more changes than any other job we have seen before, they'd still have a great healing arsenal as a dps role. Also see paragraph 4 here.

They could try something like add no mind or int to the class and have the job crystal add primarily piety and modify the effect of cleric stance. In a conversation I had with a friend a while back, the idea was to (possibly) increase the power gain of attack spells in cleric stance further (possibly) reduce healing more and add stacks of a buff that increases spell speed by casting one type of spell (ie. aero I/II or stone I/II). The advantage to this is that they don't have to change many abilities effects, for that matter the lv30 job ability could be "Cleric stance 2" that does the aforementioned things. The trade-off for a system like this would be that they have much more base mp in a fight and if used for healing outside of the dps stance would have the capability to outlast most other healers. That said, the increased mind and abilities from WHM/SCH may put them ahead in total potency healed with just their base mp in general circumstances, and WHM/SCH would definitely outperform on a hps scale.

If they went with a holy-centric job, I think "Cleric" would make sense, you know..... "Cleric" stance and all.