With any photographic technique I think we should also look at the subject matter/content it's being applied to. I mean, Gregory Crewdson is using a similar process, making multiple exposures of the same scene and piecing the negatives together, and is generally considered to be an important figure of contemporary photography. At its core his subject matter banal: neighborhood streets, suburban houses, empty main streets - all topics favored by a great deal of the medium's icons, but it's the small details, the glow from inside a parked car or the mist caused by a puddle evaporating or the smoke of a distant woman's cigarette that cause us to get lost in the pictures. One would imagine if we were staring out from the same spot as the camera we might only notice a fraction of the details which Crewdson has highlighted for us. His technique is used to compliment this mission. His pictures are "manipulated" only enough to get us to take notice that something peculiar is happening here, and after that we easily transition into a world of heightened clarity but one that is very possibly the world we observe around us - it's just a matter of wanting to look at it.
What I'm saying is photography as a medium has always been driven by technology and technology has always determined what kind of pictures we could make. Often times what has happened is the technology has moved faster than the ideas, so there are periods where the potential for great and thought-provoking images is there but we haven't reached that point in the analytical or conceptual realm of the medium. Obviously it's a chicken and the egg situation, as far as technology/technique and subject matter go (and it greatly depends on what subject, which technique/style/ect) and sometimes the subject comes first and the technology must "catch up" to meet it.
So HDR? In the end it's a technique that has probably not been completely expanded on or explored, and while it has been a part of some important work, it is still unknown if there will be more instances of technique and subject happily coexisting, as in Crewdsons pictures, or if it is doomed to become over saturated and deemed a blip on the radar in the eyes of the medium's historians.