I am a total control freak, and usually play households of 4-8 sims. My playing includes a lot of pause-button and switching back and forth between sims...
That's because, like you SimPoseyYum, I've noticed both of those things you described.
First of all, if I let them do even one thing as they please, they do something that's a total waste of time. Like play computer when their fun moodlet is maxed etc etc.
Recently I've also noticed that the queue seems to disappear when I switch to check another sim. I noticed this recently, I'm sure it didn't happen before on my games. I got LN some time ago, and was thinking maybe it's the celebrity thing (photos/autographs cut the queue) but I tested it, and often the queue disappears at the moment I enter map view. Not always, but often... VERY annoying! I'm wondering if something in the game changed in some update, because I never had this problem and then it became common.
Also, I have a feeling that sims that are not "watched" are less productive. I've noticed the same thing with my fisherman, he might fish all day but not accomplish too much if I just leave him there alone. I was thinking I might be imagining it, but you're now saying the same thing... maybe it is true.