and for #3 that if you are at a table where players CAN pressure you to play your PC in ways you don't want... you should get away from those toxic players as quickly as possible and the game would be doing you no favors in putting in rules to just try to and reduce their toxicity to you. If you play with jerks... wanting rules in the game just so the jerks don't hurt you as much is not a great look and isn't something I think WotC should be doing.
I mean, I'm not trying to be rude, but I think it's representative of a real problem with discussion online that you immediately leap to talking about "jerks" and "toxic" here. And not just because Britney starts up in my head every time I read that word
Players "pressuring" you aren't necessarily being jerks or toxic. They may well not even be conscious that they're doing it. Very often they're perfectly nice people who just want a situation in the game to go well.
The typical conflict I've seen in games involves zero jerks, and looks more like this:
Player A: < is selecting spells >
Player B: "Oh we might fight X, maybe you should memorize [spell which would help significantly if that is correct]?"
Player A: "I don't like that spell, I've picked these, they'll be great!"
Player B: "Oh okay, um... cool"
Or
Player B: "Can you cast [insert cool buff or similar] on me? That's an awesome spell!"
Player A: "Nah, I didn't memorize it this time, I have [spell I probably won't cast/obvious junk spell]! It sounds cool!
Player B: "Roger, it's a cool spell though!"
And obviously it emerges that the player memorizing the spells screwed up in a sense, because that spell would have made a big difference, and whilst there aren't recriminations, there is a vague sense that the player is maybe a bit of a ditz and their PC maybe a bit useless. Often this is quite ongoing because the player picking spells is just a bit quixotic in their spell selection period.
But this hits "Known" spells to in a slightly different way. The same quixotic players (who are often extremely pleasant to game with because they're fun people and often good RPers) are the people most likely to end up with a Known spell selection that
If it's at jerk levels you have something that looks more like 2E:
Player A: < is selecting spells >
Player B: "Okay Cleric, we need you to memorize X, Y and Z [all heals/cures] and retain your spell slots to use those!"
Player A: "But I'd rather memorize these other things, we do have healing via [whatever]!"
Player B: "Well if you're not a team player... I guess you can do what you want..." (or worse)
And if you're using "I'm just playing my character" as an excuse when you screw over the rest of the party then please leave. You are the one being a jerk.
Hmmmmmm.
That can definitely go either way, because what is "screwing over the rest of the party", exactly? Seems vague as heck. Like
1) Rogue steals the loot from the other PCs and runs off, uses excuse "I'm just playing my character!", sure both player AND PC are jerks.
But
2) Cleric chooses spells she thinks are a good idea (and which may or may not, in fact, be a good idea!), and also says "It's what my character would pick and I don't think they're useless!", but X other party members want her to memorize just heals/cures/etc, and think she's being a jerk for failing to do. I would suggest it is in fact they who are being jerks in most cases. You want to control what the Cleric memorizes? Play a Cleric.
Then there's the more confusing:
3) Wizard picks a bunch of obviously-not-great to near-useless spells that the player knows perfectly well are pretty crap. All of this, unfortunately, matches well with the personality/style of the character, are they being a jerk? What if other players ask them to take more sensible spells?
I've seen all of these, none are theoretical. In the last case, I've seen it more than once, but with Known spells (a Sorcerer), no-one bothered them about it because they knew it couldn't be changed, and eventually people just got used to it and confirmation bias kicked in and we only remember the times those spells worked out, which, like, wasn't often, but hilarious when it did.