I'm going to be a bit lazy and not answer each person specifically, but I do, very much so, appreciate the thoughts. I'm taking it all into consideration.
I'm extremely fond of Prateem's and rangda's posts and thoughts (and I know they weren't the only ones to entirely mention it, but it's described in more detail there so I can build more thoughts off of it).
I *think* I'd like to try and implement that. However, it'll most certainly take a type of scripting.. And honestly, I'm not sure if I can do it that way. Each spawn point is a localized point, so the other spawn points are interdependent.
My idea is that, using DLL as a base (it'd be a requirement for it, really) to get the encounter zone, parse the editor ID for the type (or have an array of all the encounter zones, but parsing the type would be better), and determine if it should potentially have different types of spawns through an array of the zone types. If it does, it sets a global variable with a random value, which is then used to set the type of creatures spawned. There'd have to be some checks to make sure that happens before the new creatures are spawned. Through some object oriented scripting, maybe we can refine that further..
At the moment, though, my decision is to not change the reset tags on the encounter zones; I think it'll be too unrealistic when moving around. The minimum levels should provide more than enough of a base difficulty level for each area. Any further editing will require more advanced scripting, but these are very, very interesting possibilities to massively increase replayability and variety in the game.
This'll also come tagged in with leveled equipment list changes, so there won't be any thieves in full glass/ebony, for example. And actually, that happens because several of the lists were flagged incorrectly; it should only be a 1 in 4 chance or so by default anyways.
*If* Dave can get encounter zones up in SkyEdit (should be easily possible), I'll later throw out an optional for zones to reset, because of his nifty batch edit feature.
And of course, this is also assuming that flag does what I assume it does..

Edit: The only annoying thing I see occurring is that DLL could erase all of the custom placements; no draugr sitting in a tomb. Could possibly mess with those hunters sunbathing, for example, too. Not sure how much that'd bug people.