I am aware of the nostaligic essence and the salty appearance but beyond that, wouldn't it be technically inferior compared to conventional modern sail plans on a 30-40 foot sloop?
The modern sloop is more a product of modern materials than anything else. Being technically inferior is not something I think is of as an issue. Inferior implies it won't work as well and gaff rigs have worked a long time. They still are practical on modern multi masted boats. The gaff rig is quite well developed and could be considered more modern than many other types of rigs.
We have a tour boat that sails
here out of Yorktown, VA that went to South America
for the winter. They sail using the gaff rigged sails
not just put up the sails and motor
around. They do motor
to keep a schedule but it is amazing how two people handle the boat for a whole tour season here. This boat is considerably larger than a 30 to 40 ft sloop.
I think it would be a mistake to take a modern sloop and somehow think it would be optimal to make it into a gaff rig or attempt to redesign a gaff rigged vessel as a sloop as some form of superior technology. It's like delineating how an orange is unlike an apple and so is an inferior apple. The history
of boats is as much a study of the history
of material science as anything else. Boats have always required well developed technologies to operate. Cost and other materials properties have been critical to all boat designs. Applying those technologies to a gaff rig design yields fine boats.