It's one spell per long rest. For a Wizard, they have to 1) obtain a scroll, 2) spend two hours per spell level copying it, and 3) supply 50 gp of special materials per spell level, and 4) take 8 hours of long rest, and 5) spend 1 minute per level of the spell to prepare it.
This is a very meaningful part of the wizard class. Their versatility was in that spellbook. It was rare that anyone "needed" to change more than one spell, but the ability to access more spells through that spellbook for that average-one-switch per night was critical to their versatility. And now that versatility is actually significantly worse than the sorcerer who does not have to jump through those hoops to do the same thing.
Are we not going to count the fact that the Wizard has more spells known than the sorcerer to begin with?
I mean, by 5th level a Wizard knows 14 spells with zero "found" spells added... and likely can prepare eight to nine of them, while also having access to rituals which are likely at least another two or three spells, so the Wizard would have immediate (or within 10 minutes) access to about twelve spells. Compared to the Sorcerer's 6.
And yes, now a sorcerer can sleep for eight hours and gain access to spell #7, by losing access to spell #5. And spell #7 could be any spell. Any spell at all, as long as it is on the sorcerer list.
And the wizard can still find a spell, and if it matches their school they can spend an hour and 25 gp per level to get it in their book. Having now access to 15 different spells. (I'm not counting the "take a long rest and prepare the spells" part since it is assumed by the sorcerer getting a long rest)
So, at what point does getting spell #7 or 8 match the Wizard who has twice the options at any given time, from a larger and more powerful list of spells?
Except in practice, it's usually just one spell you'd change anyway. There are diminishing returns that ramp up quickly the more spells you're able to change because most of the spells you choose you will want the next day anyway. It was always that ability to switch a small number that was the heart of wizard versatility. Most circumstances where you'd want to change more than one, are also the circumstances where you could take more than one long rest as well.
And in practice, Sorcerers have so few spells known, and many choose only the best possible spells, that it is an incredibly hard decision to figure out which one spell to drop for another.
The reason why wizards and other casters only change a few spells, is because their core spells are too good to replace. Sorcerers have nothing but those spells, so the circumstances of them replacing any of them, let alone all of them, are ludicrously small.
There is only so much differentiation one can have. A Fireball is still a Fireball, and when they roll initiative, Sorcerers still bring the same number of spells to an encounter they did before.
I'm less concerned about the mythical power gamer that is going to sculpt their spell list over a weeks worth of long rests than the player that quickly picked their spells 2 minutes before the session started and realizes they've "made a huge mistake". I am DMing a party where the Rogue still has to be reminded what their attack bonus is.
Exactly. A power gamer is going to be doing well regardless, they will have the perfect spell list, and a combo planned for it. They aren't who this rule is meant to help.
You know what I truly and dearly hope happens? I hope to see a Sorcerer swap out Phantasmal Force or Hold Person for Detect Magic. Not because that is an OP spell that will perfectly encapusulate yadda yadda yadda, but because that is a spell I have never once seen a Sorcerer use, but that I think they should have.
And they don't use it, because it is a terrible spell for a sorcerer to learn, I mean, as one of your two spells at 1st level, it certainly isn't topping any lists. But, it would be fun for them to be able to use detect magic while in the city on downtime. And not feel like they have ruined their character forever.
I see it the other way around. When your DM gives you permission to alter your character sheet by DM fiat, it's a retcon. When there's a game mechanic for swapping your available spells, it reflects something your character does.
What I usually do is emphasize that "knowing a spell" isn't at all the same thing as knowing how to roast a turkey or install a motherboard. It means having a complex and delicate magical process suspended and ready to activate at a moment's notice. You're not casting Magic Missile from scratch every time, you're feeding power into the previously prepared formation and letting it activate. So when you swap Magic Missile for Absorb Element, you don't "forget" how Magic Missile works. That sort of abstract magical knowledge is covered by Arcana. What you're doing is tearing apart your Magic Missile spell formation and using the parts to build an Absorb Elements one instead.
I find that detailing spells like this makes so many of the D&D mechanics make more sense than treating them as simple learned skills. You can do similar things for martial classes swapping out Maneuvers or Fighting Styles. It's not a retcon, they're not wiping their memory of old skills, they're changing their off-camera daily routine to train different combat techniques. They still know the theory of the other moves, but can only reliably perform the techniques they're staying in constant practice with.
A very good way of keeping track of it.
Wizards lost a lot. They lost their niche.
They lost because everyone gained something save the wizards.
1) I am not a player. I am a DM through and through.
2) This rule is totally unbalanced. Because some DM were not sympathetic enough to allow a player to change a spell once in a while because he made a mistake, we are now stuck with a rule that destroy the very reason why wizards were fun to play. Versatility.
Everyone now has a great versatility. With just one feat, you get what the wizards have left: "ritual caster". So why make a wizard then? Because you have the feat right of the bat? A poor choice if you compare ritual caster with sorcery point.
I guess that IF wizards were given wizard points for metamagic, the sorcerers would scream for INJUSTICE! Yet, since it is only the wizards that are on the losing side of the equation, everyone is perfectly fine. Sometimes, you have to see the whole picture and not just one part of it.
So many other modifications could have been made to the sorcerer to make him better and respect his niche without infringing on the wizard's niche. But WotC went for the easy way and screw the players that liked wizards.
And sorcerers lost theirs at the end of 3.5.
But, you are also wrong about Ritual Caster. After all, Leomund's Tiny hut may be a ritual spell, but Aganazzar's scorcher isn't. neither is Bigby's Hand. Demiplane, Animate Dead, Glyph of Warding.
I'm sure we could go on, but a Sorcerer (base class) does not have access to a lot of the wizard list, even if they do end up using their feat to take ritual caster.