Letting Wizards learn any spell from any scroll is gamebreaking IMO.
Not just from a mechanical standpoint - by making D&D's strongest class even stronger, but it actively hurts the class fantasy of D&D. Not only does this invalidates every caster class by letting Wizard learn their best spells, it hurts the Sorcerer who sees the spells known gap wide. It especially hurts Paladin and Rangers (half casters) - because a Wizard can potentially learn and cast their best spells BEFORE they can. It's a direct attack on Bards and one of their class features - Magical Secrets
The Bard's Magical Secrets is a level 10 feature that lets them learn spells from every class (but limited to a very small amount, i.e. you get 2 by level 10, unless you're a Lore Bard). This is going to be a one of the "capstones" for a single class Bard in BG3... and we're basically going to let the Wizard have a version of that for free?
This is the same issue with Bonus Action Hide, or Free Advantage on Backstab/High Ground - it invalidates very specific class abilities. Can you imagine how silly Reckless Attack would look if we still had backstab?
Yes, in theory you can help limit this by limiting the scrolls available, but now other classes can't have scrolls to supplement their casting, because the Wizard needs to be better?
