I don’t think the Swan class plans have any issues, Roland Vlahovici world and european champion built his Pegasus based on that plan set.The builder skill is important too.
your correct there are really no issues with these hand drawn old school plans the point is they require a little more work by the builder and a higher set of skills, nor are they suitable for the new wave of model building with computer aided tools
what Joe and others are doing is on the very cutting edge of model engineering anyone old school or the computer geek with all the high tech tools can use the plans in different ways. You can not take a plan of the Alfred by Harold Hahn and print a figurehead or stern carvings the plans have to be redone in order to do that.
it is not a question of what was or even what is it is what will be and how do we lay the ground work