No, good mappers won't. Bad mappers would, but does anyone care about bad maps?
Firstly, dp sucks at open maps. It's not dp fault but dp was not designed for this. If you can't make good open map (good are sev's or cluefull newbs maps), why bother at all.
These open maps are the state of ART, but not very useful for actual gameplay. You tend to lose focus looking at the pretiness

and of course they tend to drop fps alot on slower pcs.
Secondly, nexuiz community has a lot of very good mappers. Currently they were focusing into dm, but maybe everything will change, cause nexuiz already has a lot of good dm maps. Maybe organizing contest like ctf map of the month would help and somehow awarding the winners. Look how good morphed contest went (even lurking I read everything).
Thirdly, pure terrain maps are borring. Why? I'm not going to cite mikeusa. His post should be somewhere around.
Nice open maps should be much bigger than they are now. Consequently, they would require some convenient means of transportation. All games having nice large open maps had some means of transportation (far cry 1-2, hl2, >= ut2004, bhd, halo).
Finally, and the most important thing nexuiz is (was?) old school shooter. Of course, it can change, but old school means came, saw, made a pile of gibs and not picked up a tank or camped while hidden in the bushes.