No argument from me about fly-back reusable craft (assuming launched from
EELVs) being preferable to water-landing capsules. Dry landing capsules, well
maybe.

However, isn't the orbit of the ISS non-optimal for departure/return lunar
trajectories?

I'm in favor of attachment of an XM to the ISS for research studies into long
duration/ self-sustaining spaceflight. But cyclers (traveling habitats :-)
probably have to depart and return in different orbits that the ISS is not
optimal for.

?

Dave