Malicah

Ok so who cares if it requires the previous expansion. As people have said, of course you will have to have the previous so that you can level to 70 to be able to survive in the new area.

And then those saying "Well new players to the game will have to shell out all this money for expansions" You have to think about the fact that it takes TIME to level. It's not you buy wow and you immediatly HAVE to buy the expansions, it takes alot of time to level to 60, which until you do that you really don't even need to buy BC, and then the same applies to 60-70, you don't have to buy the next expansion till then.
So really you only pay for them over time and when you are ready and WANT to move on in the game, plus that should give you the reason why Blizzard shouldnt bundle BC for free with the new expansion, the people that should be buying the new one should already have BC, and those that need BC shouldn't be worrying about the new one yet.
I believe the best options is that blizzard merely lowers the price on BC and as someone already said, eventually after a few expansion make some anniversary addition with the first few expansion added in.