It seems now the world generation will not only change with 1.8 but also with 1.9 which should not be too far out in the future. So I posted a question to Mojang at reddit regarding the world generation. If you have a reddit account, please upvote it so we have some chance at an answer.
Uncovery Minecraft
I upvoted and also tweeted this at Notch and Jeb. Hopefully they see it!
i twittered him and jeb about it as well :D
(this was actually my first tweet :P)