The current page protection scheme has always been very flat. It takes a pretty much "all or none" approach to page protection that's simply anti-wiki. Right now, there are two basic forms of page protection:
- autoconfirmed — allow only certain users who meet hard-coded requirements to edit a particular page; and
- sysop — only only certain users in a particular user group to edit a particular page.
These two options kind of suck. Page protection should be much more flexible. For example, it should be possible to protect a page from any user with less than 100 edits to allow users who are clearly established in the community. Or it should be possible to limit based on how new a user is (more than just saying the user must have been around for four days as the current system requires).
Tim and I have discussed this type of feature previously. He suggested doing it in groups or levels or tiers or whatever, so you could standardize and simplify the scheme a bit. On-wiki configuration of these tiers would be ideal, of course.
I'm not sure if this particular RFC would allow for better granularization of page protection, but if so, I'd stress that in making the case for implementing this idea. I'd focus on the "opens the page up to more people" argument rather than getting lost in gated trunk models and other things (which are honestly kind of separate issues).
I think the extension part really is a no-go for page protection. Though as Daniel notes above (I think), the waters are getting muddy here because it's unclear whether you want something more akin to better page protection or something more akin to a hybrid of Extension:Drafts and Extension:FlaggedRevs.