Larian didn't do any DLCs with DOS 1 and 2, so I highly doubt they would start with BG3. Which is a part of the reason why I like them so much.
They do content and feature updates, so as far as that goes; I believe they stated that we will be able to change the appearance and class of Origin characters in the full game, so if anything that's the only thing I really wish for to come. Whether it is a vanilla feature or a feature for future updates, I really want it.
