Strongly agreed. What made it so flavorful is... well, one, forcefem. But two she wasn't doing it to get a lover or slave. She wanted a little sister to love on and teach which is actually a rather wholesome thing to yearn for. That yearning element and the complete lack of morality/ethics in trying to get that wholesome thing is just much more hyper-intense to me than it'd be if her desires were wholly impure.
I suppose the next plotline will be Fake White Hero Alma learning to look up to Runa as an older sister/mentor and stripping down as a means to gain bravery and confidence by imitating her?