Virtually every scroll that requires concentration is much less useful because you lose concentration quickly, even without environmental damage. Which limits the number of meaningful turns quite a lot. As for the list of useful scrolls, I'd say it's much shorter in BG3: Blur, Misty Step, Mirror Image, Healing Word. The rest of them are very niche.
Also, the number of scrolls is very small and anyone who knows how to play would never waste a level to be able to use scrolls for some good but extremely rare spells.
Magic classes don't need them, and that is unlikely to change in the full game. At the moment, the only classes that make use of scrolls are those that cannot use these spells.
If you add the rng component to them, you will make them useless and in most cases it will not make sense to waste turns on them due to the high chance of failure.
Concentration spells are indeed riskier for melee characters, although this is offset by having high AC, high Con, and proficiencies in Con STs. Or ranged martial characters will take less risk. Barbarians actually cannot Concentrate while raging, so these scrolls will be useless for them, but we'll see if Larian sticks to that rule.
The final OP'ness of spell scrolls will be heavily determined by what Larian does with splash damage. If they largely reduce the # of enemies with fire flasks and make it so that characters get a ST to take 0 damage from surfaces, then Concentration spell scrolls will be
much better.
I agree that magic classes don't really need scrolls (aside from wizards copying to their spellbooks), with the combination of the ability to freely change prepared spells AND the lack of rest restrictions. But I don't agree that the solution to this is to freely allow non-casters to use scrolls. The solution
should be to fix casters such that they get more benefit from scrolls. If martial characters can use scrolls without cost, then this muddies the classes too much. Why bother choosing the Eldritch Knight subclass when I can just use scrolls
and get the benefits of a Battle Master?
Also, we theoretically will reach the city of Baldur's Gate in Act 2, where there will be plentiful access to buying scrolls. Considering the ease of acquiring money in BG3, I expect that we'll be able to purchase basically any scrolls we want.
