I like some of this theory, I think there is a good argument to be made that Shar or Selune is the Absolute in collusion with the Illithids, but then you get to Wyl who has a number of people to corroborate his backstory (including a Baldurian player). It'd be very interesting if select memories were being suppressed by dream-entity in order to make our investigation harder, or better yet to lead our investigation towards being captured again.
I think there is ample material in the game to tell you who Shar is, mostly from Shadowheart, and I also think there is going to be much more on the way.
Yes. I think there will be plenty of material to tell us who she is in the game. The point of this post, however, is that the game needs a very basic description of who these goddesses are prior to Shadow hearts reveal. It's not about whether they're actually going to tell you who these goddesses are at some point. It is simply about the player being able to learn that information via a dice roll or a cutscene before Shadow heart tells them her Secret. That way, they can respond in the more intelligent manner to her reveal.
By the way, I was only joking about the fan theory. My real fan theory is that the absolute is it actually the main villain in throne of bhaal. 😮. Raised back to life after the second sundering.