Yeah, I think it's a very good mechanic, in the end.
I hate the concept of asymetric lines of sight, but without cornershooting, we'd have to radarshoot all the time instead... (damn, makes me think I gotta try a gunrunner nanomachic something-launcher)
Still, I think LOS can be fixed & improved :
- fix enemies attacking you from squares you don't see
- show enemies LOS (something telling you, at least, if a particular monster can see you would be a great improvement)
- fix shotgun spread, or show affected tiles when aiming, possibly with degrading colors to illustrate damage dropoff -> big improvement in accessibility, and more ergonomic.
- Oh, and fix this one, btw
http://forum.chaosforge.org/index.php/topic,6287.0.html