As it is, the rules change in after hours trading as many have reported on ET when they didn't get filled... hedging with OTM options just to protect an account overnight is costly and awkward. Many are flat at the end of the regular session. 24/7 markets might encourage away from daytrading actually...
I think it will eventually happen as more and more other countries forming exchanges, doubt it be better as more is usually not good for the account as it often makes more over trade. Also, many more would be screwed by HFT wanting to trigger stops. Just cause USA might get rid of it, if another country on Saturday morning is open and their USA indexes plunge would trigger others to do so as well. If China was smart they would go 24/7 and make access to their markets would spurn other countries to do as well. More jobs be added and instead of cartoons you loony tunes watch on Saturday mornings, your wives and GFs will have another reason to get rid of you. HAAA
I agree we need 24/7 especially if its a wet boring weekend. Weekends are when i have the time to trade. Not for any other reason though