Part 7: Level 3 & 4 MagicLevel 3 Black Magic
FIR2: Like FIRE, but stronger.
BLT2: Like BOLT, but stronger.
TMPR: Raises a character's attack power.
CHRM: Charms all enemies, making them fight each other.
Level 3 White Magic
CUR2: Like CURE, but stronger.
HLY2: Like HOLY, but stronger.
MUTE: Silences all enemies, stopping their spellcasting.
WILL: Raises the party's resistance to status ailments.
WILL seems like a really good spell, but in practice it's kind of lackluster. It's okay when used to counter enemies that inflict ailments through their attacks, but spells tend to have such high accuracy that it's effectively worthless against them. MUTE is another spell that's situationally useful; most bosses are immune, but some enemy spellcasters can be really dangerous, and MUTE can shut down groups of them. TMPR is a staple for boss fights; it will eventually be outclassed, but in the meantime it's going to pull a lot of weight, especially because it can stack with itself. By far the best spell at this level, however, is CHRM. CHRM hits all enemies and not only stops them from attacking the party, but turns them on each other. It's one of the few spells in the game I think is broken, and should definitely have been placed at a higher level.
Level 4 Black Magic
ICE2: Like ICE, but stronger
COMT: Deals dark damage to one enemy.
HSTE: Doubles the number of attacks made by one character.
BIO: Inflicts sleep and poison on all enemies.
Level 4 White Magic
HEL2: Like HEAL, but stronger
CLNS: Removes all status ailments except death and petrification from the party. Works on poison, but can't be cast out of battle.
SLD2: Like SHLD, but stronger.
LIFE: Out of battle, restores one character to life. In battle, deals damage to one undead enemy.
BIO, I think, is overvalued here. If nothing else I think it should be switched with CHRM, since adding sleep to it isn't a huge improvement over regular POIS. HSTE is an amazing spell for boss fights, effectively doubling a character's damage output with attacks, you can bet I'll be using it in every such fight once Ranger can get it. SLD2 mostly makes SHLD obsolete, but there are times when the lower-level version might be a better choice (especially out of boss fights). LIFE was already a very good spell in vanilla; its new lower level and secondary effect (which does considerable damage) are just icing on the cake. CLNS is also a fantastic spell, especially later in the game, when enemies start inflicting more ailments, especially in one shot. Overall, white magic users do a bit better at this level than black magic users, but HSTE is still a great spell, and of course direct damage, while unexciting, is always useful.
COMT is also worth mentioning for its damage type: dark. You'd think that, in grand RPG tradition, resistance to this would be far more common than weakness to it, but that's not the case. It's actually a very effective spell and worth having around if you can spare the slot.