I have a feeling that Alleria will die tbh, as much as it would suck just after finally meeting her.
(I really hope we can tattoo our elves like that in the next expansion <.<)
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I think the titan model we saw in the patch stuff is probably going to be Sargeras, I know it's nothing like him at all, but I think Sargeras most likely does not have his own body anymore and that is why he now needs a host to move around. Thus "Argus the unmaker" is likely going to be his spirit inside of that titan.
That is probably why the pantheon is still alive as well, for him to have a number of hosts for his spirit. Illidan was one of them but that failed.