The problem, as I see it, with a complete tear down in the mile events is time. Mile events are weekend events with hard-in-fast start and stop times. (We are at the mercy of the folks who really own the track) I can see averaging two runs, but what do you do when a first pass qualifying run is set on Sunday afternoon at 4 pm? Where is the time for the second run and tear down? If you compress the event to "only qualifying" runs can be done on Saturday, then I see foresee a major safety risk. Instead of doing a shake down run or two, a lot of guys, because of time, will go "all out" on their first run.
Of course we could hold a mile event using the same setup as Bonneville (two run average and engine tear downs), if Stan would donate enough money to the ECTA to purchase the land and build a dedicated track.