I haven't lost any followers and I haven't followed anyone else, but that's not because of the activity feed, it's because I've always been careful to keep my circle small.
I will say I'm enjoying the new feed. The point of the activity feed, to me, was always about pictures and seeing what people in your circle were favoriting. Why not make those exact pictures bigger so those items are more obvious? I find that having them so large shows them off to their best advantage and I'm much more inclined now to click on and perhaps favorite an item I see, whereas before they all tended to blend together.