well, for give my cynicysm here, that is probably exactly the response Blizzard wants. They seem to want the faction change, name change, race change, etc. to be a big enough deal that players will not do it on a whim but consider it and only do it if they really want to. Then after you've done it they want you to not turn right around and go back.

Setting aside the obvious RP/lore issue of 'how does a human suddenly wake up as a tauren?' there are lots of other issues including the economy of the servers, etc. There is a big market for vanity pets for example where people will buy the 50 silver pets from the various vendors in the major towns then transfer them to the opposing faction through the neutral AH, and sell for a 1000% markup to the opposing faction.

I could extend the argument to gold farming as well but will stop there. The point is there is a lot more to this than some warlock on the Thrall server wanting to be a human on Frostwolf. This could have a significant negative impact on the game if they aren't careful.