The 5e rule for casting from a scroll is actually far more restrictive:
-You can only cast a spell from a scroll if it is a spell on your class's spell list (so e.g. a sorcerer could cast Daylight from a scroll, but a wizard could not)
-If the spell is on your class's spell list, but is a higher level than you can normally cast, you have to make an ability check with your spellcasting ability (DC based on the spell's level) or else the spell fizzles and the scroll is wasted.
And a wizard can only copy spells that are on the wizard spell list into their spellbook.
I would love to move to something that is much closer (or identical) to this. A wizard going to a store and buying a spell scroll to copy into their spellbook feels pretty normal and reasonable. Leaving tons of spell scrolls laying around the world and letting anyone use them takes away the things that are special about classes that can cast spells without scrolls.
I wonder, how does book of shadows come into this for warlock, since you can inscribe ritual spells from other lists into it? (Or I think you can, been awhile since I rolled one up with tome cause I have a bias with chain)? Something closer to the rules you mentioned might be good and help classes feel distinct though so I agree. It would be both a buff to Wizard as they will be able to take advantage of scrolls the most but also a nerf cause some of the more broken things they could do would no longer be an issue (like randomly learning healing and then outdoing shadowheart on healing).
