Hassel's got it.
If you say you were hacked, they may lock the account or otherwise make the process longer, more difficult, and tangled. Just saying "hi I'd like to update the email on my account, I no longer have access to my current email." If they ask why you don't have access to it (they really have no reason to ask, but just in case), then, if it's an email from an ISP, like comcast.net, then just say that you no longer have that ISP. If it's a gmail or yahoo address, just say you forgot your password to it. Never say or even imply that the WoW account in question has been hacked, or that you don't know the password to it, or something.
Inconspicuity is key when recalling.