I feel that people don't always see that the 2 styles require different amounts of space; a sport climb needs about 2 arms width (2 m) between routes (1 arm or 1 m either side). If you place a sport route that close to a trad route, the trad route dissapears.
I suggest that (without cracks or other defining features) that a trad route needs at least 3 m either side, more on long pitches, and even more if the route is a wanderer (such as "climb crack for gear with frequent excursions for a few metres either side to reach the jugs").
A lot of these 'top new routes' are based on both the impressionistic lines on photo-topos, and also on the notion that you can rightly bolt sport routes a metre and bit to one side of an old trad route.