Spellcasters in general are best against numerous weaker opponents. With only a handful of exceptions, single-target spells do about the same damage as an equal-level area spell, and debuff/control spells are generally weaker than in PF1 or in 5e, with a more graduated effect. In PF1 or 5e, a debuff is generally all or nothing: a successful save has no effect, and a failed save does something pretty nasty.
For example, in PF1 hold person is "save or be paralyzed with a new save each round." In PF2, paralyze has these effects depending on the target's save:
Critical Success The target is unaffected.
Success The target is stunned 1.
Failure The target is paralyzed for 1 round.
Critical Failure The target is paralyzed for 4 rounds. At the end of each of its turns, it can attempt a new Will save to reduce the remaining duration by 1 round, or end it entirely on a critical success.
So you see that in order for the target to be paralyzed for a longer period of time, they need to critically fail. A regular failure only paralyzes them for one round. But on the upside, even a successful save gives them Stunned 1, meaning they lose one action next turn and can't do anything until then (no reactions etc.).
But as a second nerf, paralyze has the Incapacitation trait. That means that if the target has a level higher than twice the spell level (which by default is 3, but a prepared caster can prepare it in a higher-level slot for a stronger effect, and a spontaneous caster can either learn it in a higher-level slot or take it as a "signature spell" letting them spontaneously upcast it) the target's save result improves by 1 step, so a normal failure becomes a normal success, and a success becomes a critical success.
Incapacitation is a trait you'll find on strong debuffs like paralyze, blindness, or charm – the kind of thing that takes a foe out of the fight completely (even if temporarily). Weaker debuffs like fear or slow don't have that trait.
