I think if the page protection scheme is going to be redone, it should allow for customizable protection levels. The current none/autoconfirmed/sysop configuration is highly inflexible and often results in people being forced to choose the lesser of the evils.
It should be possible to specify that a certain page can't be edited or moved or created by people whose accounts are newer than X or who have fewer than Y edits. I'm not sure if this belongs in a separate proposal or should be incorporated into this one, I just think it's desperately needed and that any rewrite of the protection logic should include it.