Hey there.
I've decided to make it my mission to work on as many jobs as possible, playing as a casual player would, to detect and report any problems or abnormalities with jobs. Not so much I feel these can be fixed without the DarkStar Project Team working on Core, but more to show others how jobs will play. This will be an updating list as I level and play jobs. Note: Most merit point enhancements do not work, so I am not going to spend the time examining each one individually.
Red Mage
Job Stability: Stable/Normal Gameplay
Major Problems: No major problems with job spells and abilities. All 75+ Spells and Abilities appear functional.
Spell Bugs: A few of the spells seem unaffected by the 'Fast Cast' trait, and on other jobs these spells seem to cast slower (e.g. Aquaveil)
Job Ability Bugs: None, Composure, Convert, Chainspell, and Saboteur all work properly. All sword weapon skills work.
Scholar
Job Stability: Slightly Unstable/Working but Lacking Main Features
Major Problems: Stratagems do not work properly, depleting the main capacities of SCH
Spell Bugs: No major spell bugs found other than mislabeling of effects of 'Weather' spells in the chat log. Klimaform spell works but uses incorrect casting animations. All other SCH specific spells function as intended.
Job Ability Bugs: Tabula Rasa non-functional for stratagems. Stratagems themselves do not appear while under effect of 'Arts' unless leveling up. Most strategems will function fine once they appear unless zoning, changing 'Arts', or using 'Addendum: Black/Addendum: White'. Other than leveling up no current way to make stratagems appear in Job Ability list.
Summoner
Job Stability: Stable/Working but Lacking Minor Features
Major Problems: Diabolos does not have any blood-pact abilities, Astral Flow non-functional, Spirits do not cast spells but only attack
Spell Bugs: All SMN spells except Odin summon the avatar/spirit, even Alexander can be summoned w/o Astral Flow.
Job Ability Bugs: Diabolos has no blood pact rage or ward. Diabolos can only attack physically. Some of Carbuncle's ward spells are non-functioning. Fenrir, along with the 6 main avatars function perfectly for all attacks/buffs. Alexander can be summoned, but acts like Diabolos only doing physical attacks and no blood pact abilities like Perfect Defense. Elemental Siphon, Mana Cede, and Avatar's Favor does not work.
Dragoon
Job Stability: Stable/Cosmetic Errors
Major Problems: None
Job Ability Bugs: Soul Jump and Spirit Jump are functional but they use the incorrect attack animation. Same goes for Dragon Breaker. Otherwise the job abilities work as intended.
White Mage
Job Stability Stable/Lacking Some Functions/Spells
Major Problems: Job trait Divine Veil does not function, nor does Afflatus Misery.
Spell Bugs: Auspice can cast but does not create the enchantment. Esuna works on the caster but not on other party members.
Job Bugs: Divine Veil is not in the job trait list, so therefore cannot be used with Divine Seal. Afflatus Misery does not work at all.
That's it so far. As I keep going through jobs I'll update this post.