Let's just be realistic. In my opinion, buffs should be limited to:
1) Friendly buffs. (No Mind Breaker and Provoke.)
2) Party buffs. (Anything that if cast, goes to the whole party.)
3) Buffs that can be cast onto other players. (No player/class-specific buffs such as EDP, Maximum Overthrust, True Sight, Energy Coat, etc.)
4) No +status food buffs.
In short, only general buffs that anyone can do by themselves should be cast by the NPC on you.
These include:
Acolyte buffs:
Blessing
Increase Agility
Angelus (could be left out, or added in as a "risk" about using the full buffer)
Priest buffs:
Impositio Manus
Suffragium
Kyrie Eleison (or skipped in favor of Assumptio)
Magnificat
Gloria
High Priest buffs:
Assumptio (rather than Kyrie Eleison, since only either one can be cast on a player)
Crusader buffs:
Providence / Resistant Souls
Blacksmith buffs:
Adrenaline Rush (only applies for Maces/Axes)
Weapon Perfection
Over Thrust / Power-Thrust
(For the sake of completion, but shouldn't be added is the Spirit Skill:) Full Adrenaline Rush / Advanced Adrenaline Rush
Soul Linker buffs:
Kaizel
Kaahi
Kaupe
Kaite (may be skipped in favor of Assumptio, Kaite cancels Assumptio upon cast)
Sniper buffs:
Wind Walk
Alchemist/Creator buffs:
(Chemical Protection should be left out.)
Input/comments are appreciated. But these are the only realistic buffs you can give yourself in normal circumstances.
These buffs already give a huge advantage in PvP separately, combined together it should be enough for a "Full Buff" so to speak. We don't need every class having buffs that are class-specific.