In the past week I have heard 2.0 called
"A Rebranding"
"An Update"
"An Expansion"
"A fix for earlier problems"
"A Redesign"
and "A new game"

SE needs to make it clear to the media what "A Realm Reborn" is, as anyone looking into it will be ultimately confused.
Why does any of this matter?

For one, "a new game" is metaphorical/rhetorical. It's not literally a new game, not even by a longshot. Even if everything was changed, it sitll has the same title, just with a subtitle tacked on.

I think the most accurate terms would be the ones SE itself has used "Redesign" or "revamp."It's not new, but it's not old either. It's not strictly a fix-up, either.

I don't think they're trying to sell it as an expansion. That wouldn't be a good way to market it. Outside of that, I'll just let the people at SE that know marketing handle it.