There's essentially two brands now and women's division is more plentiful and competent (for the most part) than ever before, so two nights just makes sense to get enough shine for everyone and not bloat the shows. 7-8 hours spreads well over two nights. Even 5 hours is a bit much for 1 night and it's too many good potential match ups for the big show to only splice them down to 3-4 hour formats anymore.
If they did one night now, a lot of good matches would get left out and I doubt they could put enough women matches on the card as well, as either they'd really stifle men's division in trying to even the odds or short change the women's entirely. As it is now, even with two nights, some great talent still gets left out.
I would prefer one night so I wouldn’t have to put other shyt off on a Saturday night.
It's one weekend of an entire year, duke. I'm sure you can manage.