I think the main challenge of the waitlist is that ANA releases more seats usually 2-3 weeks prior. When your outbound trip gets its chance to be cleared, your inbound trip may still be way out of this window. And then you are kicked out of the waitlist 14 days before the departure of the first segment.
From what I observed it seemed you could actually hold the available seats for return on your waitlist reservation. So I grabbed some random flights towards the end of the calendar for return while waitlisting my first outbound segment. This way my waitlist should be much easier to clear, and I can change my return flights later when close-in availability opens. I'll know in about a week if this actually works.
But I do already have a confirmed seat on JL booked via AS that is cheap to cancel (US$12.50). I'd be very anxious if I didn't have a back-up plan. In fact the main purpose of this waitlist reservation is to burn off my ANA miles that have turned out to be so painful to use and are almost inevitably going to rot.