I am sure it would pull out some interesting issues and, to some extent, help identify what it is about a T list site which might be noteworthy and add value in linking such sites to their inscribed fellows. BUT, a few contrary thoughts
a. A lot more work for Els
b. T List sites are often not well documented. A fair number of WHS Connections depend on very detailed site maps, advisory body evaluations and full nomination files in order to establish their credentials! Proving/demonstrating a T List connection without such evidence could become too much a matter of assertion and opinion
c. I don't think they should be mixed together in a single list as that would compromise the integrity and value of the inscribed site list. Whilst the T List contains some very good sites many are pure "kite flying" by the countries concerned and the main list shouldn't be diluted with such "thin beer"!
d. But that in turn could create a logical problem -e.g would we allow a connection with, say, only 1 inscribed site but 2 T list sites or would all "connection subjects" have to be justifed at the inscribed site level first.
e. It would take our eyes off the ball on the main list - I am sure there is still more to "discover" there!