I think I may have figured it out: an app 'Apps Organizer' I believe, was having some issues loading its widgets, and so caused other widgets to load slowly or even fail. I was getting a Process System is not responding message also. I noticed one of the three widgets I used for this app was stuck loading, as well as other widgets, and thought maybe this is the culprit (stopping the others) and deleted that widget. Rebooted and everything loaded ok. I'll use old fashioned folders instead from now on.