I guess what it boils down to is that I incorrectly assumed that the FBC travel agents were taking those factors--short connection time, travel time from the airport to the dock, and last call for embarkation--into consideration when offering it to me. Mea culpa. That does not change, however, that I am now unlikely to use them in the future. I normally do my own bookings and if I had seen things on paper, I may have thought differently when looking at all of my flight options. My use of FBC for this trip was mostly due to my cruise companion wanting the assurance that we'd have some protection in case we missed the boat. We had already purchased CruiseCare before we made the flight arrangements.
Just to clarify on the service I received when I spoke with FBC last night: they told me, more or less, that I would not be able to get assistance from them until I actually did miss the connection. They added that they would not be able to change my flight since it looked like there were no other flights available--I'm certain that isn't their fault but due to restrictions on their ability to change bookings that the airline itself could handle with little problem. When I asked about what options I had right then, they had nothing to offer except that I contact the airline to see if they could change my reservation.
What would have happened had I actually missed my connection is now a mystery. It's likely I would not have arrived in Frankfurt until after 10 a.m., missing the flight. The only flight option at that point would be a FRA-FCO flight over an hour later that would get me into Rome around 1:30 p.m. Getting through customs and to the cruise terminal before the boat set sail would be a real challenge. I'm glad that I don't have to see how that would actually play out.
Also, separately and not directed at any one responder--I'm a he. 🙂