This may have already been proposed, but a sound for when someone replaces a player in the lead would add to the game's atmosphere.

I don't think that's hard to implement, but then is it necessary? I don't think so.
If it has to be there then it has to be for all games not just Farkle. It isn't so much different than setting a table master which doesn't make a sound.
At least when you get kicked it makes a sound because that's a bit more informative, and I think it just makes you leave the table forcibly so that's why you hear the sound.

I guess you mean when someone is in the lead right? so not when you replace people in general. I can see how it could be useful

I don't think this is about replacing a player, which has a very specific meaning here on the Playroom, but rather when a player overtakes the lead. RS Games Farkle has a sound for this.

For example: Bob has 300 points and Alice has 200. On Alice's next turn, she banks 200 more points to make 400, overtaking Bob's lead. In RS Games, the sound for this is different than the normal banking sound, and this increases tension.