I think that the Southern 'Metro' network should be added into TSW2020, including Metro lines to Epsom Downs, Caterham, Tattenham Corner, Beckenham Junction, Selhurst (inc Depot), Horsham to name a few. Now that would be worth the extortionate 25 quid for each map!
This area is like a spiders web of lines heading in so many directions that the possibilities are enormous in number. Great idea though.
As big of a shame as it is, we know DTG wont do multiple branches. Although the route would be nice. XD