I don't know if this has changed in Rome, but if not I would throw it up for consideration. Because if you look at this picture, who could tell me which routes I have upgraded and which haven't been? I guess maybe the dots have meaning? But it's not explained anywhere, and only now do I actually notice them.
Thanks for the suggestion. Supply line upgrades have actually been dropped from Rome. They were a fairly hasty addition to Gold and we didn't find they really added that much to the strategy. In Rome you have a lot more flexibility with your connections, so you can improve your resource flow just by re-arranging your routes or building camps as waypoints.
So far, I think the feedback has been pretty positive on the changes.