Doesn't openspades give a massive disadvantage because you can't see gunfire on the map
Supposedly, but I don't particularly mind because dang is it pretty. Sound engine's good enough that I can locate gunfire by ear in 3D better than I would with a 2D map anyway.
you can barely hear grenade explosions
I haven't used the default sounds in ages, but you can just replace the distant sounds if you want.