Strahd got mentioned again, and I have never actually touched any version of that adventure. But my brain always goes, "He's one vampire Michael, how many paladins would it take?" And that's because in Pathfinder 1E, Paladins were goddamn terrifying.
So real quick as far as combat effectiveness: Fighters are above average at everything and you can specialize them however you want, Barbarians are quick and easy damage machines that you won't see get outclassed unless you compare then to a Ranger vs their favored enemy or a Paladin when they get their smite on.
This is also the appeal of fighters is everyone else can exceed them but it circumstantial and relies on a resource(rage/smite charges) or a specific target (favored enemy/evil target). If the others don't have access to those things then the Fighter will just outclass them.
But Paladins just... christ they were good. Their only bad saving throw was Reflex, Dexterity is also their most common dump stat. BUT they got to add their CHA bonus to their saves in addition to the standard stats, so they usually have the best overall saves in the game besides monk.
But what does Smite Evil actually do? First, you add CHA to attack bonus and AC vs that target. Then you add your level to damage rolls against them, if they are undead, draconic, or a devil you get to double that damage bonus on the first hit. Finally, you just ignore any Damage Reduction they have. And one charge lasts until either the Paladin or the Foe are defeated.
To compare: A lv 4 barbarian rages and gets +2 to attack and damage and -2 to their AC. A lv 4 paladin smite could easily be getting a +4 to attack, damage, and AC.
It's amazing and makes all the Oaths worth it. And god have I been disappointed by every system to follow.
5E's smite is just... burn a spell slot for extra damage. They don't even have to be evil. But yeah a couple extra dice on one attack in exchange for a spell.
PF2E got rid of the Paladin entirely and replaced it with Champion(i will DIE MAD). And I went to look at what smite even is in the new player core... oh right they didn't even include them.
