I honestly can't decide what I am looking forward to most, there are so many things.

I am looking forward to spending hours in character creation, trying out all the new options that have been added for full release.
I can't wait to see how much act 1 will differ on full release from what we have now.
I am super curious how the companion's backstories turn out - particularly Shadowheart and Astarion.
I will definitely play evil, so I am very curious about what Larian have done with it.

.. and so many other things. Sure, I am worried about the occasional thing, but all in all, I am incredibly hyped to play when it comes out, no matter what.