Well, Firstly, I am only referring to those earned by level. I dislike the fact you are asked to 'choose' spells to memorize for cleric et al in the same way a bard might, because it is implying a feature incorrectly, aka that you only have those spells. Secondly I am not sure it would slow down the game quite so bad as when I manually drag them everytime. Having played a Necromancer recently with 12 skeletons all having lines of sight I am aware of potential slowdown issues (I had to get my DM to turn their sight off) but every single time I play a Cleric I drag all the spells into my book, which is simply work that the charactermancer was supposed to do, and don't suffer over it. As for the slowdown, they already make alterations to the way the spells are added, with them being opened or the innate line being visible across a second line instead of a first - so with that much tinkering perhaps a way to store spell data more concisely would prevent that issue.