Don't forget that the levels are for the most part randomly generated, and most as the effects the OP describes needs to be scripted. The levels, compared to other RLs, are very small, so such effects would have to be very rare.
Raising and lowering bridges? Sounds fun, with some of the recent new level layouts.
Triggering ambushes is already implemented, and not only in special levels. Sometimes a vault is open by a lever even in a normal level.
Increasing or decreasing LOS can work similarly to Light-Amps, that are already present, and while it sounds interesting, it also sounds a bit redundant (you do have the light-amps already, and "dark-amps" would mostly simply force the player to hide until the effect wears off).
One way switches and persistent switches - can you please elaborate? I'm not quite sure what to make of it.
Switches active only for a limited amount of time - nope. I personally operate switches only when I either have Int, or when the level is safe, or when I'm really desperate. I would certainly never hurry to a lever just because it may disappear.