Can someone explain to me what's so great about witches?

If you weren't into it before you might not be into them now if any occult is coming. It's more so speculation than actual evidence.

I did like the witches in S2 as much like other occults that showed up in the game they were a rarity and pretty fun when I saw them.

Witches in S3 I found pretty boring. Considering the majority of their spells were mostly just cheats that you could do in some other form. If they do bring them to S4 I hope they're definitely more of an improvement over what we did have much like the rehaul on vampires were they seem a lot more interesting. Considering they can break into your home and bite your sim if they're sleeping.

For the most part occults are more so just a nice novelty to play with now and again less you're someone that wants to play with them all the time.