Presently, questions from new users are shown and can be answered immediately, although they also go into a dedicated review queue (https://mathoverflow.net/review/first-posts).
Since a significant part of the blatantly off-topic questions on MO is from new users, one might consider displaying first questions from new users only once they have successfully passed the review queue. --
Do people think this would be a desirable change?
If yes, would it be feasible to do?
Edit: I think the answer by Francois G. Dorais and the comments by quid give valid reasons why using the review queue for such premoderation might be not such a good idea.