Brian, you make a great point about strike detection. Though not always the case, often times, even with an indicator, it requires one to have a "sixth sense" in order to detect a strike, as the take can be so soft, so subtle that the indicator fails to respond noticeably to it. In this regard, nymphing streams and rivers without using a strike indicator has really helped me to develop that sixth sense, which helps me tremendously when fishing chironomids. Using as small of an indicator as you can is very important (or do not use one at all, at least when you are fishing in deeper water).

Some people do not like "staring at a bobber" all day, but after a while, you can really begin to pick up the most subtle, almost imperceptible takes if you really are observant and pay attention to how the indicator responds under various conditions. As you said, "unnatural" movement or motion of the indicator always must be followed with a hook set.