Adjust qualifying times so that the new qualifying time is the average time of the last three years for the 75% person qualifying time for each age group. For example, if the qualifying time is now 3:10 and 75% of the people who qualified in that age group qualified by running 3:05, the new qualifying time would be 3:05.
Have the registration open in October. In January have a week window for people who registered a time to return their entry for a partial refund. If there are people who have run the new faster qualifying time and want to enter but couldn’t because the race filled up, those spots go to the new qualified runners. If there are still some spots open, run a lottery of people who have run the current (old) qualifying standards.
I think they will likely say you can use a qualifying time only one year at Boston. This makes sense to me. As it is now, I could use Malibu for twice and that doesn’t make too much sense if the race is too full now.
1) The race fills up.
2) It decreases the number of no shows.
3) The faster runners will likely get in.
4) People know what they have to do to get in and for almost everyone, they will know the day of their marathon if they qualified or not.
The order of these three things is not of importance.