I got a new asus tablet for Christmas. I upgraded the tablet with the latest updates. Since then I have no clock or date on my lock screen. This tablet is not rooted and I did not do any modifications to it.
When you look at your list of widgets, are there any clock widgets? If there are clock widgets, you can hold the widget icon and drag it to an empty spot on your home screen, and then you'll see a clock.
I had the same issue. I tried a bunch of different things, none of which worked. Looking through apps to see what may have caused the issue I noticed the "MyAsus" and thought I'd check there for support. Turns out I didn't need support, as once I registered/logged into MyAsus the no lockscreen clock/date/weather problem seemed to be sorted. I don't know if it was just coincidence, but it won't hurt to give it a go and see if it works for you.
Thanks. Just tried it and it works! Probably won't buy another Asus tablet for a while because when I try and update the Asus apps it says their not compatible with this device. So I just disabled all the Asus apps and replaced them with better alternatives but other than that the tablet is an amazing device.