I love that the challenges grow according to which areas the wizard has unlocked and finished, but I think it would be even better if they limited it to areas that we can currently use, incase we don't have membership at the moment.
The game is designed in a way that there's still so much to do if somebody doesn't have it, like fishing in castles, gardening, petmaking and such. I think it would be nice if daily assignments would be the same way.
Not saying it should exclusively be limited to the free areas in Wizard City, but atleast the ones that an account has bought with crowns. I've got plenty of those, and it's a pain when I can't do the assignment because I happen to not have that area permanently bought yet.