I think it's too late to change that
That is not exactly true and i believe that skilled modder would be totally able to cut whole map into smaller hubs with some screen message telling you something like "you were travelling for 3 days in a forrest".
Kingdome Come Deliverence. It has interesting map and fast traveling system. Its really trying to fix it. Try to give you a sense of bigger world but yet offering fast traveling option too for occasional use.
I wouldnt mind if Larian changed to use that. Good Features should be used in game industry. While Im it, I think War Horse should take Narrator from Larian. Narrator could help KCD's fast traveling, if you get attacked, Narrator could talk you in.