The night lighting levels are very much a matter of personal taste and will also depend on monitor settings and how light the room is. I'm therefore not at all surprised that you felt the need to adjust the .ambientlight settings. I find that somewhere in the region of 25,25,25 is great when driving in a dark room (at night, lights out) but on a bright day, something much higher is needed (eg 200,200,200). It must however be rememebered that at night, not much will actually be visible outside the range of the train lights.
One drawback with changing the ambient light settings is that it will affect the glow of some of the illuminated objects. This is a particular problem with some of the lighter coloured platform walls which have been coded to glow to simulate reflected light.
It is also worth noting that development of the night route was performed using a flat panel display - I have yet to see it on a CRT but can imagine it looks a lot better as it will be less sensitive to viewing angle.
A final issue regarding the night routes is dial illumination in the cab - not sure how to change this so that the dials shine brightly.
Personally, I am looking forward to more night routes - if properly done (which does take a lot of effort) they will add a whole new dimension to BVE.