I'd like to get into a whole thing about this matter, but one of my main games right now is Torg Eternity, where you get a whopping three spells by playing a spellcaster. If you're from the magic cosm you can get five. If you play the one exact right kind of spellcaster (like, a specific cosm/race combo), you can eventually get as many as eleven from a very weird and particular list of spells. And you can't ever change them. (You can in fact get more in any of those cases, but the rapidly escalating XP/spell ratio makes it a bit crazy.)
Eh okay I'll get into it a little bit.
The whole point of
spells as opposed to powers is that you cast them through ritualized action (however brief, and in D&D it's historically very brief!). The action can be so exacting or tax the brain so much that you forget bits (original Vancian magic), or you just have to really bone up every day to be sure you've got it primed and ready, but you should be able to do that retuning. The time scale of the retuning could still be a differentiator. Maybe most spellcasting classes can do it on a long rest, but Wizards can do it in a minute (X times per rest, whatever). Coming back around, though, a big part of the narrative behind Sorcerers and Warlocks is that they don't do spells through ritualized action, they are in fact inherent or granted powers. So that drains a good bit of the feel/fantasy as well as the mechanics from those classes. Then again, Sorcerers have that whole wild magic thing going* and why couldn't a patron grant a different power each day, just like a deity? Roleplay that stuff!
* What if sorcerers had to roll randomly for their spells each day?

: Remember when even wizards (magic users) had to roll dice to determine what spells they had?
The slots to prepare thing is just weird and arbitrary. But then so is the concentration mechanic, however well-motivated it is in gamist terms. But slots prepared is a bit more complicated than number prepared, so it seems to go counter to the direction they're going. I don't know what their reasoning is behind this. It's definitely a nerf.
Three spell lists is too crude. Specifying a combo of list + schools winds up being more complicated than just having class lists, which again seems to go counter to the direction they're going. These are effectively just class-specific lists, except you don't even get the list that you can just look at, you have to go digging through multiple lists at best, individual spell descriptions at worst. I think Pathfinder 2 struck the right balance with its four lists, and with having Sorcerers/Witches get a list based on their patron. But dang is that system crunchy and full of undiagrammed feat chains/trees and "this feat gives you that spell so flip pages back and forth to find out what all you can do" (exactly the problem I pointed out with list + schools, hmm...).
I'll add that the supposedly simpler "you have these spells, unless you pick from this bigger list" is terrible textual organization and really muddies things. They should just have a separate section or sidebar with "the quick build".
There's much more to come down the pike though, so who knows?