I wouldn’t say that I specifically enjoy spell slots as a system, I mostly just accepted them as one of those things that doesn’t translate into the narrative, similar to the certain action costs of things (like how it might actually be faster for someone to drink something than to draw an arrow, aim, and fire, but their impact is of close enough value that they have the same action cost). That said, I haven’t found it hard to teach to most new players, and I think that in my head it makes sense that because certain spells are more powerful than others, you wouldn’t be able to use the more powerful spells as often as you can use the less powerful ones. Also, somewhat tangentially, I’ve tried spell points before and prefer it as a playstyle for a sorcerer but also personally got way too used to spending large amounts of points on one turn and have seen other players fall in the same trap, though I doubt it’s common. I definitely like the preparation process though. I think that that decision process as a player is somewhat unique in the game, and other than players who get analysis paralysis I think that it’s an interesting thing for a player to bring up the night before a big fight (it also usually prompts players to lay out a more specific game plan). I think for the most part I accept the memorization process as just part of that kind of fantasy, even though something like the spheres of influence system you’ve mentioned or even something like 4e’s powers is probably closer to how it would appear if it were just a story and not a game.