Isn't the notion of a reset button to undo the first season just a fan theory? There has been no official information to indicate any such thing, not that I've seen. The teaser implies time travel or an exploration of alternate timelines, but that's a very different thing than specifically undoing development they just spent a full season exploring.
I saw a lot of similarly outrageous fan theories ahead of season one, which alarmed a lot of people here, but none were proved true when the show actually aired.
I find it easier to be optimistic than to assume the worst. We'll find out soon enough. And going into it with an open mind makes for a far more enjoyable viewing experience!