Every “special rule” you come up with only further complicates the game. You just do this, guys - you make transports the way they were for 24 years.
In 2004 before all of this tinkering with the rules Larry Harris said on his site “Transports work well and always have.”
Transports defended @1 because they were assumed to be escorted.
Now there are DDs in the game that defend @2.
However, there were still many types of escorts that took part in WWII protecting transports that were not as good as DDs but still offered some protection. There were Merchant aircraft carriers, Catapult Aircraft Merchantmen, Armed merchant cruisers, Corvettes, Frigates, and Escort Carriers. These can be represented by making the transports defend @1 as they used to. This is 1/2 the strength of a DD escort.
Stop the reminiscing “when we used to play back in the 80’s, blah blah” - it won’t work that way anymore - now BBs take 2 hits, subs cost 6 IPCs, and DDs are a purchase option. You bump the classic transport up to 10 IPCs and call it a troopship, which is what it is anyway. Nobody is going to be fool enough to use them as fodder anymore.
And best of all: no special rules. They fit in nicely with the rules already in place. Plug them in and just play.