This is a terrific conversation!
1. Though I have enjoyed PortlandHikers on Facebook, this kind of experienced, knowledgeable, in-depth debating is really a Oregonhikers.org forum specialty, and I'm glad to see it flourish.
2. TLDR: the Park Service basically has this problem solved, and it annoys me to no end that the Forest Service can't use the same techniques.
I'm generally in favor of active management, as well as more access. In the absence of a critical environmental concern (such as the Larch Mountain Salamander), I believe that we should encourage access by citizens. However, the management component is important. In the case of Memaloose Hills, interpretive and LNT signage, trailside fencing and hardscaping, and even ranger patrolling might ameliorate the likelihood of flower trampling. These solutions are far short of excessive, meddlesome permit processes or area closures, and would look familiar if you've visited Paradise at Mt Rainier, or Rim Village at Crater Lake. In short, these are tried and true methods that the Park Service uses to manage crowds effectively.
For an experienced hiker, these solutions offer little barrier to enjoyment. I hiked in Zion Canyon National Park last month and had an absolute blast. It was crowded, and there were a few unfortunate boot paths, but they're taking great care of the park. I'm sure you can find examples of failure to contradict me, and that's fine if you're inclined. But can you find a better model of crowd control? Seattleites have been used to their backyard mountain being a tourist destination for decades (dear Aimless: great point about the distinction between hiker and tourist). We in the Portland area are just getting used to seeing our backyard mountain and Gorge experience the same discovery and impact, with the distinction between our two cases being that our most beloved local destinations are USDA forest farms with small wilderness areas dotted around, not well-managed Parks.
I think we can all agree that the FS doesn't have enough money to do its job, and that all of my potential active-management solutions require funding currently unavailable. Another issue is the speed of change: without adequate boots-on-the-ground staff keeping an eye on their properties, the Forest Service could not possible react quickly enough to prevent the sudden influx of tourists after an Instagram bomb of a formerly lonely place like Memaloose Hills. Similarly, the time required to complete an EIS and public outreach processes would be an impediment to saving beautiful hillsides. It'd take so long to get approval to put up some fencing that all the flowers would be gone by the time it's approved.
All I can say for myself is that my solution is dead on arrival, but it ain't my fault! We coulda had a lot of rangers and trail building for what we paid for the Iraq War or the last round of tax cuts for billionaires.