UA articles are proposed changes to the game put out for playtest purposes. They are generally not yet balanced. They aren't just toys for us. If they are rated as popular, they get published in official products. The reason why those who don't like the way something is done in a UA should care about it, is that now is the time to provided feedback so that when they do put out the product with the finished version we are happy to buy it.
I almost never use UA materials in my games, because they unpolished and unbalanced. I usually allow in actual published content, and I'd prefer that content be of as high quality and as useful to as many people as possible, which is why I'm tearing into this material and trying to get everyone thinking about it, so we can figure out stuff about it they may not have thought of (the purpose of a playtest).
I don't agree with Mr. Crawford's apparent view of the wizard. I see daily flexibility as merely one component of the wizard's identity. My Premise B flexibility is another vital component.
I think I probably was misreading something he said, but it almost sounded like he was saying that the specific spells a wizard knows are part of his identity--which I think is exactly backwards. The ability to not be limited to specific spells is a part of wizard identity, whereas knowing certain specific spells is part of the sorcerer's identity. This is where I'm seeing an identity confusion.
It sounds like you don't accept my Premise B (which is actually my assumption--that anyone who disagrees with my concerns does so because they have a different concept of wizard identity that doesn't include Premise B). The sort of flexibility that you explained is an important part of wizard identity. If there were a proposed change that took that ability away from them, even if they gave them something like Spell Versatility (which I don't think wizards should have either) in exchange, I wouldn't like it. These are two halves of the wizard's identity to me. I have daily preparation flexibility, and I'm the most likely to be able to find that one spell we need.
I'm an equal opportunity identity guardian. See my sorcerer threads for how I think they are underprivileged compared to the wizard in flexibility. Spell Versatility is a wrong way to handle it, because it takes away a vital part (Premise B) of the wizard's identity.
I do not necessarily disagree with your premise B. I do disagree though that Spell Versatility is taking away a "vital part" of premise B.
If the party leaves their home village at level 1, the sorcerer has 2 spells they know. The wizard has potentially 6. That is three times the number.
When the party encounters the challenge, between having 2 spells and having 6 spells, who is more likely to have the
specific spell they need, right then.
The wizard, because they have more spells available
in that moment.
A Wizard with an Int of +4 will consistently have more spells prepared than the Sorcerer knows. And, they do not need to prepare any ritual spells, having them available anyways through their spellbook.
Yes, on a long rest the Sorcerer can swap any single spell from their entire list. But, as I showed, they cap out at having 9% of their list available to them
in the moment. Even just counting prepared and ritual spells, wizards have double the amount of spells ready to go than the sorcerer, and looking at the numbers they could have as much as 30% of their entire spell list available within the day. A spell list almost double the size of the sorcerers.
So, the sorcerer is only taking a "vital part" of the wizards ability to be the most prepared if within that massive number of spells known, the wizard does not have the same spell. And of course, this is entirely ignoring the impact of magic items on the two.
I disagree that we have somehow crippled the wizard's position. They have lost nothing of their advantage, the only time when the Sorcerer can take this role away from them is when they were not going to be able to solve the problem anyways.