Spoke with Rostyslav in IRC. I suggested extracting nui to a tera library with anything that needs to go with it in the first instance. The issue with extracting to gestalt is the extra work involved reaching an acceptable quality level necessary for me to include it in gestalt, not only for NUI but for all of its dependencies (game assets, input, maybe math). Plus I'm tossing up whether to use tera-math or joml(-immutable) for the math library for gestalt.
I've also suggested starting by integrating gestalt-asset-core into Destination Sol, just to see if it works for android as-is.