[quote=@Bacon]keep in mind that establishing an in-depth faithful recreation of a Persona game's mechanics is not the objective here. If it were, I'd be asking for stats and be providing specifications on how that works.[/quote]

Fair; I suppose nitty gritty details like damage-boosting passives won't even come up in an RP setting. It's just a bit hard to translate a system where you usually want to stack passives on everyone to one where numbers don't actually matter.

Anyways, I think we should go for tertiary focuses, though we might want to dial it back or forward based on the category. I would mostly reference the party members of Persona 3-5 for what each focus should entail.

So, here's me trying my hand at an actual suggestion of how things would work:
[hider=For real this time]
Primary Phys: Charge or Crit rate passive and Colossal-damage attacks (or their multi-hit equivalents)
Secondary Phys: Severe-damage attacks and one Colossal-damage attack (single target or AoE)
Tertiary Phys: Severe-damage attacks or Lucky/Miracle Punch
Flavor Phys: No higher than Medium-damage

Primary Gun: Charge or crit rate passive and Severe-damage attacks
Secondary Gun: One Severe-damage attack (single target or AoE)
Tertiary Gun: Crit rate passive for guns (since Snap has a high crit rate, crit knockdowns are the idea. Ideally in line with Lucky/Miracle punch, or we add in other gun skills to compensate for the lack of them)
Flavor Gun: No higher than Medium-damage

Primary Magic: Focus and either both Severe-damage spells or Megidolaon, or perhaps a unique skill that's stronger.
Secondary Magic: Focus and one Severe-damage spell
Tertiary Magic: one Severe-damage spell
Flavor Magic: No higher than Heavy-damage. Element break skills are allowed.

Primary Healing: All healing skills
Secondary Healing: Either (Diarahan, Mediarahan and Amrita Shower) or 3 of (Diarahan, Amrita Shower, Samarecarm, and Recarmdra)
Tertiary Healing: Diarahan or Amrita Shower or Recarm
Flavor Healing: No more than Dia / Mabaisudi / Me Patra / Energy Shower / Lydia

Primary Buffing: Luster Candy / Hyakka Ryouran
Secondary Buffing: Heat Riser or Matarukaja, Marakukaja, Masukukaja, Dekunda, Rebellion, and Revolution (or something like SMT5 Cautious Cheer / Red Capote which performs two team-wide buffs in one move)
Tertiary Buffing: Matarukaja or Marakukaja or Masukukaja or Dekunda or Rebellion and Revolution
Flavor Buffing: Tarukaja or Rakukaja or Sukukaja

Primary Debuffing: Debilitate
Secondary Debuffing: Matarunda, Marakunda, Masukunda, and Dekaja (or something like SMT5 Stagnant Air which performs two debuffs in one move, or SMT Strange Journey's Armshot/Legshot/Cripple gun skills that lower attack/speed/defense with attacks)
Tertiary Debuffing: Tarunda or Rakunda or Masukunda or Dekaja
Flavor Debuffing: Only Sukunda

Primary Ailments: Something like Magatsu Mandala or Phantom Show; a heavy-damage attack that inflicts ailments or a custom skill with higher odds of inflicting ailments.
Secondary Ailments: Any non-unique ailment skill in P5R (i.e. the attack skills too)
Tertiary Ailments: Either Elemental Ailment Boost passives and one single-target non-damaging ailment skill or one non-damaging ailment skill
Flavor Ailments: Makajama only
Note: Bosses are still probably immune

Primary Defense: Persona Q's Safeguard and Body Shield (Takes damage in place of one/all allies for a turn), The actually strong evasion/other defensive passive at Bacon's discretion (e.g. things like Ali Dance, Firm Stance, Holy Embrace, or SMT5's Kannabi Veil or Luminescent Mirage), plus the weaker defensive passives like Regenerate 3 and High Counter
Secondary Defense: Persona Q's Safeguard and Body Shield, Regenerate 3 and High Counter or similar passives
Tertiary Defense: 2 of: Persona Q's Safeguard (Takes damage in place of one ally for a turn), Regenerate 3, High Counter, Tetrakarn, or Makarakarn (or similar passives)
Flavor Defense: Counter
[/hider]
So, notes:
- I figure Luster Candy should be on the table since Yusuke gets it, albeit under another name
- Having a focus means you would eventually unlock these things, not that you get them in a timely manner. While most skills probably unlock at a reasonable pace if they have downgrades to work with, something like Luster Candy will probably have to sit on a simple aoe buff for a while before eventually getting Heat Riser, Thermopylae, and finally Luster Candy.
- I think buff/debuff stacking is ideal since it allows for more overlap with characters. [s]Also I'm biased since the mechanical concept I'm going for with Mermaid relies on it.[/s]
- Am I weird for thinking Heat Riser is useless when auto-buffs and Vitality of the Tree Thermopylae are so accessible? I mean, I know that that doesn't apply here, but even just a bunch of aoe buffs are more turn-efficient for buffing the whole party in the long run.

I included guidelines on what qualifies as a flavor ability since there's probably a gap between flavor abilities and abilities meant as intermediaries for people who actually want to focus on a category, though you could of course modify those as well as you see fit.