there was an idea like this on the old forum
the reason it didn't pass was not because people didn't like the idea but because the server wouldn't be able to handle something like that, replacing the much lava with air all at once would most definitely crash the server
even just reflooding with air, if they were to do it too much fast than the lava floods initially it would create huge amounts of lag, which is why lava is set for the speed it is