I regard the smaller ships (100-800) as expedition ships, not as cruise ships. The way I see a cruise ship, the ship itself with its entertainment and activities, is as much a destination as the ports. I have been on an expedition ship (99 pax) to Antarctica, and it was a totally different experience on board compared with all the cruise ships I have been on.
If the larger ships (say 1,900 passengers +) aren't cruise ships, what are they?