I just recently really focused on playing a sim through it and my only real problem is that as others have said it's just not that challenging. For one thing my sim is on track to have every possible perk; there's no balancing effect like the weaknesses vampires have to take and a lot of them do very similar things. And some of the potions are extremely powerful for very little cost - if I can use a single apple to make four potions that completely restore all needs, why do anything else? I've downloaded a couple of mods but I'll have to check out the list posted above for more.
Edited to add: More RoM mods and spells can be found at Zero's Sims 4 Mods here: https://www.patreon.com/posts/realm-of-magic-35030446