Yes, additional mods could be added. There is more work involved than just a straight port, though; for legal reasons, the Larian mods based on workshop mods were created without using any of the content from those mods (the paperwork involved would have been more work than what could have been saved), and being official, would require localization in all supported languages, more thorough QA (people would be less accepting of conflicts or issues than with workshop mods), etc.