Before I go into criticism I'll that I fully appreciate what your trying to do with this project and have enjoyed the game, especially since not many people try to do this. However, I do find the fact that casting spells with scrolls are limited to specific classes frustrating especially with revivify. I can understand restricting powerful spells like fireball and lightning bolt to only wizards, though I still disagree with that design choice, but only giving clerics the ability to use revivify scrolls makes the game more punishing for players that don't have a cleric in their party especially at lower levels. I understand that according to the 5e rules that spell scrolls can only be used by classes that cast can cast those spells but I've played with many tables that lift that restriction and its beneficial, and I think it would be beneficial to this game. If you really don't want to do this, I'd at the very least lift the restriction on revivify scrolls.
I think this is one of those things that can be included in difficulty settings: allow all classes to use scrolls or something like that.
The base game should remain as true to 5e as possible. I miss the risk of party wipes. 5e is pretty generous in the death department as it is.
But yes, optional rules would solve this problem.