About the gestures thing, I think that there have been some new animations added for viewing art. Has anyone else noticed this? People spent a lot of time in Florence Delarosa's bathroom looking at the art in there, and they seem more invovled than before.
I've seen this for quite some time, when I actually let my sims be idle enough to do stuff on their own, and I didn't even have the NLp2 until last night. So I don't think that was it. The same thing for looking out windows. I think it depends on the Sim's personality, mood, and what kind of fun objects you have in the house. If they are serious, it could be that they enjoy looking out windows just as they enjoy reading a book as opposed to juggling cups like a playful sim. It seems that I don't have sims looking out windows as much in my bigger, richer houses that have more "fun" type objects like big TVs, pool table, musical instruments, etc.
I had a sim paint a nude painting of his wife when she was younger, and they hung it on their bedroom wall. They seem obsessed with the thing. Everyone in the whole family will go in there and look at it, talk about it, and the reactions range from appreciation, doubling over with laughter, or giving it a raspberry and thumbs down. I think it's all random because it really doesn't make sense otherwise. The artist was maxed in creativity, and I'm waiting to see how much the value of it goes up when he dies.