Here's my experience in a nutshell.
Yamaha's booth (in a separate building from the rest of the show) was as my friendly succinctly put it, was more like a museum exhibit.
Roland's synth area was too loud to think as it seems to have been catering to DJ's. Their new modular stuff was fascinating on paper, but in reality it was just confusing as their modules, to me, seem very poorly labelled. I have some modular gear and got to check out a lot of modular stuff but have never felt so lost! In my opinion, the coolest thing they showed was their V-Accordion, which I was told has polyphonic aftertouch and can control all kinds of synth sounds at once (internal or external). Much to my surprise, it's something that's been around for over 10 years!! The fact that you can split the buttons, play something from the keyboard (w/ velocity and aftertouch) and also play a different patch with the bellows was fascinating to me. Talk about potential!
Korg's new synth seems very interesting. It seems like it might be something that could replace my MS2000... and with a smaller footprint as well! However, I'm not the biggest fan of the Volca's because frankly the form factor is TOO small for my taste. I really do like FM and find it ironic that even though it is that small, it still offers more controls than most of the classic Yamaha FM synths.
DSI's Prophet 6 and OB-6 are really cool. I'm not sure which I like better... the OB-6 seems to have a really good handle on choir-like sounds. The filters are really sharp and offer a lot of the sounds I like to use my MS2000 for. Incidentally, playing with the Tempests on display made me realize that the pots and buttons on mine have definitely been worn in

.
Moog, as everyone has pointed out, didn't have anything new, but they easily had the most appealing looking booth!
As far as new modular goes, (as usual) I liked Intellijel the most. The Rainmaker is insanely cool if not for its KS capabilities alone. I also really enjoyed Doepfer's Clock Multiplier/Ratcheting module-- but I guess that's been available for a little while now.
Arturia's Matrixbrute was the most impressive looking new synth by far. It seems as though there are some bugs that need to be worked out. I like the dual filters, but think that when setting up a patch, it should default to one of them instead of making the user select one... as non selection will not allow sound to get to the outputs. The matrix itself is a great idea as it is much cleaner than a bunch of patch cables. I'm really interested in how it functions as a sequencer. However, it is quite big and I think I get lost a little easily in it!
I was hoping to see more synthesizer controllers, as well as more hardware synthesizers that could take advantage of them. What I did see that interested me was the Linnstrument, Fishman Triple Play, the Roli Seaboard Rise, and the Zoom ARQ. KMI's keyboard wasn't nearly as nice as Roli's, which was quite a sensual (LOL) experience. Ultimately, the shortcoming of those types of controllers, however, is the fact that the resolution of the X, Y, and Z axes change depending on whether you are playing a 'white' or 'black' key. This is why I like the Linnstrument the best, although the Seaboard definitely feels really cool. KMI also had a prototype drum pad that supposedly might have CV available. I think a multi-dimensional, low cost drum pad with CV is long overdue! Zoom's ARQ has some really interesting potential, but there are a few things about it that confuse me, especially the fact that the ratcheting (kind of like the Tempest's Roll) feature is only available via the base unit and not via the ring portion. The accelerometer works really well. The Jamstik also had an accelerometer, but it left a lot to be desired due to the low fret count as well as the fact that it was not responsive at all (at least to my playing!). Conversely, the Fishman Triple Play pickup seems ideal for me, a guitar player, because I can just attach it to my existing guitars and have at it. I thought the fact that it uses Bluetooth was icing on the cake. My only problem with it has to do with the fact that to use it to control external synthesizers, an extra $200 unit has to be purchased, nearly doubling its cost! I thought that some kind of basic wind controller, like the kind that Yamaha used to make (that could be connected to one's instrument of choice, would've been nice. Again, Roland's V-Accordion was, next to the Linnstrument and Roli Seaboard Rise, the most impressive synth controller!
I also naively expected some kind of CV or synth-controlled lighting this year. The closest thing to it was Teenage Engineering's OP-Z and Zoom's ARQ. The OP-Z's 'video synthesizer' I thought was really cool. My biggest concern is that if the user is not given enough creativity as far as the video synthesizer portion of it goes, then it will ultimately be a gimmick. As for the Zoom, while other people have said it looks gimmicky, I think it has a lot of potential for YouTubers and DJ's. I'm very interested in it!
I'm sure there's a bunch that I overlooked, but that is my general impression of this year's NAMM.