The spell source groupings are just one example: is assigning spells to groups of classes actually appreciably "better" that assigning spells to individual classes?
It is basically the way Pathfinder 2 does it, and it works there... sort of. The difference is that Pathfinder is much more aggressive when it comes to releasing both new classes and new spells, and being able to say "This class casts Divine spells" is a smooth way of ensuring compatibility with additional material both previously released and yet to come. It's a way to avoid things like "Level adept 1, alchemist 1, arcanist 1, bloodrager 1, cleric 1, druid 1, hunter 1, investigator 1, oracle 1, paladin 1, psychic 1, ranger 1, shaman 1, sorcerer 1, spiritualist 1, summoner 1, summoner (unchained) 1, warpriest 1, wizard 1" (which is from the PF1 version of
endure elements as listed on Archives of Nethys where they incorporate all the other classes).
The cost is that you don't really get bespoke spells that are adapted to the way this particular class does things. For example, the PF2 magus casts Arcane spells. That means you can't use their spells to do things that merge magic and swordplay, because they cast the same spells as wizards. Any such shenanigans have to be a class feat and/or a focus spell.
Given that D&D has a very conservative approach to releasing new classes, the main rationale for the PF2 method doesn't really exist.
Can you expand on what you find objectionable about this? Because it's one of the few thinks Perkins has ever said that I agree with!
Many of the current classes make no sense, constantly step on each others' toes, and are kept around (IMO) solely because removing or reorganising them would upset people. Barbarian and paladin are fighter subclasses, they just get their own class for purely contingent reasons. Likewise the monk, but with extra orientalism. A druid is just a nature cleric with a cargo cult built around its historical baggage. Sorcerers are wizards without hats; warlocks are wizards in corpsepaint.
In my experience, new players constantly stumble on the wizard/sorcerer distinction in particular -- it's the kind of thing a competent designer would have fixed in an early draft.
I can concur with the wizard/sorcerer differentiation in particular – it served a role in 3e where wizards were classically Vancian and sorcerers had spontaneous magic, but with the neo-Vancian 5e wizards that difference is mostly gone which makes differentiating between wizards and sorcerers hard.
But I disagree in general. In the 5e scheme, a class is what you want when you want an archetype with depth and multiple interpretations. It's like the old Psion argument. Yes, you can use the Aberrant Mind sorcerer to kinda make a psion, if you squint a little. And if you're doing an Eberron one-shot where one of the PCs is a kalashtar, that's fine. But it does not suffice if psions are supposed to be a major part of your world – it's enough for
one psion, but not enough for multiple psions with their own mechanical identity.
The same can apply to barbarians, monks, and paladins. Do you just want a fighter that gets angry, or a fighter that fights unarmed, or a holy warrior? Then they can be different types of fighters. But do you want warriors that channel primal magic in a variety of ways to enhance their fighting prowess? Or a variety of mystical martial artists? Or holy warriors dedicated to different causes? In that case you should probably have them as separate classes.
