I do like the ability for non-casters (and casters who don't have that spell on their spell list) to be able to read scrolls, but it definitely should be a difficult skill check. There's no "Use Magic Device" in 5e, so maybe an Arcana check with DC = 15 + spell level? A failure results in the loss of the scroll.
A 12-Int, level-5 fighter with proficiency in Arcana would then have a ~45% chance to successfully cast a 1st-level spell, which seems fair. Limiting enough that you wouldn't regularly do it, but in certain scenarios taking the risk might be worth it. A rogue with arcana expertise would have an even better chance, which allows them to benefit more from their skill-monkey role.
But there is the Magic Initiate feat and Multi-classing which mechanically represent just that: dabbling with magic.
Arcana refers to knowing about magic, not actual skills with it, and it would be good to keep it that way so things don't get mixed up.
