I'm not a Rockwell fan. There are many other sources of information out there, and I usually don't pay attention to what he is babbling about. His website is full of contradictions and BS IMO and his reviews are not very deep.
With your lenses, you may want to just shell out a little more and get a 610 because those FF lenses are what is expensive in the whole kit, and you are already there. That's probably what I would do in your position, depending on what lenses you have. FF is bigger as well as you note. Rockwell had an orgasm about the 610 as well, but maybe you should do some more checking.
I am sure you could probably sell your lenses as well for more than you think and get a good set of DX lenses with the 7100. Who knows what the future holds as well, with the mirrorless craze starting to take hold.
I like my 3200 for the reasons you state, and the PQ is as good as the 7100 for my use. Actually, I plan to buy a 7100 very soon because of the extra features I want that the 3200 does not have. For one thing I want bracketting instead of having to adjust shutter speed. This HDR stuff has my attention, and I will buy Photomatix soon. Check out some youtube videos on this, and Photomatix has some videos on their website.
I am waiting to see if they go on sale just before the 7200 comes out supposedly this summer, but May 1 is my line in the sand. If no sale before then, I buy it anyway. I'm going to Europe in June for two weeks, so I want to have it for a little bit before I leave. I was at the shop in Houston today and was checking out a 7100, and the 70-300 zoom. That is the last lens I need and I am done. I've also got a 16-85 that I love, along with the 18-55 kit lens and the 55-200 that came with the 3200 kit. My daughter wants my 3200 and those lenses, but who knows. If she backs out I may give it to my sister, or just keep it.
I don't know what a 'sky filter' is. I just used a polarizing filter. I don't use other filters other than a grad because it is so easy to use magenta or whatever in Photoshop. I usually take in RAW pix I know I will want to work on, and those adjustments are usually enough. That bridge pic was taken in RAW.
The more I look at that picture the more I don't like it. I was actually standing on a boat ramp, walking down it just tooling with the filter as I walked. I cropped out the ramp. By the time I got to the bottom, and adjusted a few things, the clouds had moved in. This is the only picture I had with any blue sky in it with the filter. You can tell I am not centered due to where the bridged leave the picture on either side, and it is not too sharp for the reason I wrote above. I drive to BR weekly, so I will take a tripod next time and it will be better.
Here is a picture I took with the 16-85 before I changed lenses to the 10-24 with the filter. It is completely unedited. I didn't have a 67mm polarizer for that lens, which I took care of today. Big difference this filter makes. You can also see how much sharper this picture is. The 16=85 lens has VR, and this is at the same ISO though I am at f/16 and 125 and it is zoomed in some.