It would be an another tool for hold creators. What I remember from making quake2 levels is that no ambient sounds makes it sound very empty - and unnatural.
If I could set some ambient sounds to be played in specific rooms every now and then, things would be much better. DROD would feel a bit less like a board game, what is not necessarily a bad thing.
Think about wind howling somewhere in the tunnels, something scrathing walls from the other side, muffled, eerie voices, whispers, something as cheap as rattling chains, dripping water, footsteps you can't quite place... Lots of possibilities.
And only one problematic issue: some players could use copyrighted content, and that can't be easily checked. This however can be already done with graphics.
I know a warcraft sound when I hear one.
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