Rather than count each spell as one powers slot, if you are a magic oriented character, you may instead lump spells together by level and spell class.
For example- We'll take a magic oriented OC for example here. Oumi has...
High Magic skill. Oumi has a high affinity with magic. It means she's able to cast spells that are usually a bit more potent than average. She has focused on magic all her life and continues the practice even in Iifa.
Focus- With this ability, Oumi is able to actually raise her magic affinity further. It lasts for fifteen minutes or until she is done using spells for the time being. Her spells will do even more damage or be more potent while Focused. At the same time, it also makes her more vulnerable to physical attack.
Mid Level Elemental Spells- Thundara, Fira, Watera.
Mid Level Support Spells- Cura
Mid Level Status Spells- Slowga
Low Level Elemental Spells- Thunder, Fire, Water, Blizzard.
Low Level Support Spells- Cure, NulShock.
Low Level Status Spells- Slow, Haste.
Reminder: This is only for people who are strictly spell casters (white mages, black mages, summoners, etc). If you want to combine abilities and spells, then each spell will still count as 1 power.
We take that back. Spell casters are allowed 2 high level spells of their choosing. Any of the high level spells, or varied.
High- 2 spells maximum.
Mid- 5 spells maximum.
Lows- 8 spells maximum.
These specialized spell casters are not allowed to take other abilities that are not magic related. (Overdrives, Summons creatures and any abilities related to magic and spellcasting are allowable.)