My biggest disappointment is that a majority of the spells seem to be copied from other areas of the game and just turned into spells. If I make a scientist vampire that completes every aspiration in the game to get all of the trait rewards, then that vamp would be able to do the majority of the spells in the original way. Chilio copies the freeze ray. Despario copies the trait from completing the public enemy aspiration. Etc.
In Sims 3 you had to work a lot harder to get your high end spells, they didn't copy anything that was previously in the game, and there was a lot of new unique things you could do. You could be a fortune teller, curse sims, charm them, cast spells on objects. And when you turned a sim into a toad they became a toad-sim and stayed that way until someone gave them a cure elixir or cast sunlight charm on them. They didn't just turn into a lifeless object for 5 mins and poof back to normal.
And there were 4 witch-related aspirations as well: an evil witch to raise zombies, a good witch to cure all the zombies and cursed sims, a genuine fortune teller that wants occult knowledge, and a fraud fortune teller that just wants to scam people out of their money. And fortune telling wasn't purely a rabbit hole career, you had to read your clients fortunes to them outside of your rabbit hole work hours to be able to get a promotion.
Gathering ingredients in Sims 3 took a lot more time too, and you had to grow a lot of them yourself. It was both more challenging and more rewarding. In Realm of Magic it's insanely easy to learn all the spells, only for most of them to be stuff you could already do in the game anyways. Having witches be a game pack instead of just giving us a Supernatural expansion was supposed to mean that witches would be more in-depth and would have more resources put into making them noticeably better than the Sims 3 version. But they aren't. Maxis did a great job improving vampires from their Sims 3 version, but they focused too much on the aesthetic for Realm of Magic and just copied stuff that was already in the game when they ran out of resources to put into actual gameplay development.