As I write this there are 3 flights awaiting the next improvement.
As far as I could see, at least 2 of those also diverted (to BHX).
One suspects that with a proper even CAT 1 ILS they would have probably got in eventually, and many people (pax, crews, and the folks who stayed on at SOU after usual closing) would not have been inconvenienced. Not to mention aircraft being out of place for this morning's first departures.
I love flying from SOU (and will be again in Jan), but it needs more resilience.