After much careful consideration to come up with a good question title, and entering it into the title field of the new question form, I thought I'd try out the "Ask Wizard" to see what it does. It immediately deleted the title I'd entered, and it remained deleted even after turning the "Ask Wizard" switch back off again. (I had entered some tags as well, and these were also deleted.)
This is very unfriendly. Don't delete data already entered, under any circumstances. (And yes, this has definitely discouraged me from trying out new features on SE sites.)
(That this will probably apply to Ask Wizards on all other SE sites, but it appears I need to post this separately to the meta site specific to every SE site that uses the Ask Wizard. I will not be doing this, but don't take that as meaning I don't want it fixed everywhere rather than just on SO.)