Witches, however, can go anywhere. From the Q&A we know that they can use mamgic anywhere, in any world. That’s already far more mobily than what IP has, and it’s a good sign, because it’s not srtictly tied to one type of gameplay and one environment, but you (hopefully) still get the whole pack.
And if the power tree is like vampires (which it probably is from the Q&A) then you can have a wide choice and a lot of variety. That’s also a lot different from IP. Just like the variety in familiars and witch powers, it allows you quite a lot of choices and possibilities.
All in all i’m pretty hopefull

I also don’t think it is meant to be comparable to a proper neighbourhood, but rather to a secret lot like Sylvan Glade or Sixam, where it seems to be an improvement over previous lots of this type. Sixam looks great, but all your sim can do there is find collectibles or maybe interact with the occasional alien who comes wandering by (apart from the one singular alien party event once a sim reaches the top of the scientist career: I do enjoy that event). Sylvan Glade and Forgotten Hollow have even less going on than Sixam, being places that are only notable for hiding one rare type of fish each. The main benefit of a secret lot ought to be to have reasons and incentives for your sims to go there regularly, ones that are built into the game.

On this secret lot, it sounds like sims will be able to buy ingredients, find familiars, craft potions, learn spells, form covens (if you have GT) to perform magic, meet and interact with other magical sims, duel, see other sims autonomously practice magic, and stay for extended periods if necessary (since the world will be editable with the freebuild cheat). It seems a bit like Magic Town in TS1, except that your sim can’t move there (not that it was really all that easy to move to magic town because those Magic Coins were hard to collect).