I think that you've done your homework and that your reasoning is well thought out. The new price on the D5100 is certainly enticing, and as you have said, it is almost exactly the same as the D3200.
That's the problem with almost all products from a single manufacturer, you have to decide which features are most important to you. In this case, both cameras have advantages and disadvantages. For me, I plan to take a trip to Europe this summer and I wanted small and light, and I don't want to carry too many lenses. The D3200 gives me the opportunity to leave a long zoom lens at home since the larger pixel count translates into the ability to crop deeper than I would be able to do with a D3100 or even the D5100. I also am not interested in HDR and probably wouldn't use the articulating screen. I know how to bracket manually, if needed, and since I don't expect to be taking fast action shots manual bracketing will work. I also have other cameras that fill my needs. You, on the other hand, have other requirements and wants, so the D5100 makes good sense.