One partial solution that Inyo and its partners at the VC seem not have considered is a system that Yosemite has adopted, modifying the permit-by-trailhead rule. Most rangers and permit literature will explain to you that your permit does not depend on your destination, but only the trailhead you use. Not so In Yosemite. For the Happy Isles (JMT) and Glacier point trailheads, there are separate quotas for certain first-night destinations, such as Little Yosemite Valley and Illilouette watershed. This is apparently to accommodate through hikers, who will typically blow right past the overused LYV site, hardly spending any time at all in the overused areas.
Why not institute a similar accommodation at the southern end of the JMT? I have long thought that it is an unfair and irrational restriction on would-be JMT through hikers wanting the classic south to north hike to make them compete with Whitney round trippers for trail access. ALmost as irrational as the current supposed trailhead permits which do not restrict access at the trailhead, but only at LPL and LBSL. How many JMT through hikers are going to be interested or satisfied with the mere 6 miles for the first day, to camp at TC with the Horde? Some, maybe, but even those would be spending far less time in the Whitney Zone then any over night permit holder, and use the trail less than a day tripper.
I would propose at least a no-TC permit, like the Yosemite no- LYV permits for Happy Isles and Glacier Point, and maybe a one-night only permit. This could take some pressure off the Yosemite trail heads, and accommodate the classic JMT route, without adding appreciably to the impacts in the WZ.
BTW: worst back-country dump I ever saw was Mirror Lake back in the day. Anyone remember that?