Sounds good, right? Like most of our ideas, Blizzard probably won't go for it -- they've already knocked down the idea of vanilla realms, and while this isn't the same thing (you'd be able to level to 80, the idea is just that you'd leave the server when you got there), it does mean creating a different ruleset for a brand new type of server. Plus, to a much lesser extent, it could create an even more lonely existence on the normal servers. Not to mention that Blizzard has been focusing on speeding past the low levels, not emphasizing them.
But I like the idea anyway -- it doesn't seem too tough to do (mark one realm recommended, and provide free server transfers off of it), and it seems like an excellent way to get people who enjoy leveling up all together in the same place. And that's really what MMOs like this are all about, right?