We (playtesters for the AA50) talked him into/worked with him to come up with defenseless transports based on our experiences with other games.
The main example being this game (the first edition):
That game along with Xeno’s Europe/Russia at War have more involved combat systems that allow for air to air combat prior to each round of ground or sea combat. As such, nuances like naval AA and extra warships (cruisers and destroyers) allow for defenseless transports.
Classic (and even Revised) transports could be said to have escorts (corvettes, destroyer escorts, etc.) that are included in the unit but not big enough to warrant an individual piece at this scale. That way they have a defensive number but not an offensive number. Also, the inclusion of two hit battleships and now two hit carriers have shifted the damage taking to warships.
Is it perfect? No. But the using of transports as hit takers is a joke. On the scale of the Classic and Revised games, it is a necessary evil. Only by giving the map more sea zones can you then bring in more units and start differentiating better between the unit capabilities. We were able to start that transition in AA50 because of the expansion of the map. And it continued in Global.