You bring up an interesting topic. The overnight/premarket session.
Awhile back there was a thread on ET about this. How almost all of the market movement we witness is due to the overnight/premarket session. I was blown away by that, and it made me look at the markets differently. And I agree with you, I hope markets don't become 24/7, Idk about you guys but I enjoy the weekends and letting the market digest its weekly fluctuations so you can take time to analyze and breathe for the upcoming week. This is very important.
Having market open for 7 days a week would reduce the weekend volatility just from Friday to Monday just because the market doesn't have the opportunity to digest and react to the news that came out during the weekends and then you see a huge gap up/down on Monday from Friday's prices. If the market is open 7 days a week, you would see a lot smoother continuous price movement and it would improve the stability of the market a great deal. I wouldn't mind trading 7 days a week, although 24/7 might be a bit too challenging, 8/7 or 12/7 would be fine.