The answer is all the patch 2.0 changes will go live. Things that you do have access to without RotHC like new talent trees will be available to you. However, Makeb and all it's features like getting to 55 will not be accessible until you purchase RotHC and wait for it's launch on the 14th.
Hope this helps clarify it for you.
I purchased early access to "The Rise of the Hutt cartel", and i purchased it SPECIFICALLY so that i could start playing the NEW content, and NOW you tell me we can't even get into Makeb???
WHAT KIND OF CRAP IS THIS?
Early access is early access, what did I buy early access for if we don't get early access