Small innovations: Sometimes, SHOT show is the place to showcase new innovative or revolutionary products many didn't expect. Unfortunately, this year, it doesn't seem to be the case. However, there were a lot of small innovations. Sometimes such small innovations would lead to bigger innovations, so I can't complain much.
Rise of .30 caliber AR :It's not a secret that AR platform chambered in .308 has been gaining momentum. Currently there are various offerings from various manufacturers, like Armalite, H&K, Sig, and so forth. This year a few more companies entered the fray.
However a new cartridge has been gaining momentum. .300 AAC Blackout, developed by AAC and Remington, has been gaining traction. It is not just that Freedom Group has been pushing it via DPMS and Bushmster, there are other manufacturers such as S&W, CMMG producing rifles in that caliber.
Considering that the only change that a manufacturer has to make is replacement of the barrel(other components from .223 will still work), the caliber probably will gain more momentum in next few years. It will be interesting how this development will continue.
...and more ARs and 1911s: AR rifles were predominant, and you couldn't swing a dead cat without hitting an AR rifle. Aside from obvious manufacturers like Colt, S&W and so forth, there were many others who made their rifles in this platform.
Since 2011 was the 100th year of 1911 pistol, there were abundance of 1911 makers too. It is more likely that the 1911 is now easier to build since there are more people who knows how to build one. I wonder how happy John Browning would be if he sees this.
Zombie marketing: Zombie related products are out in full force this year, as the trend has been spreading around in both mainstream and firearms world. There is no shortage of products to fill the bandwagon.
EOTech has sights that have biohazard reticles,
there are targets from various manufacturers,
(last one is not zombie related but decided to throw in)
grips from Hoguechoke,
and various weapons manufacturers
I do not know if the trend has jumped the shark or not, but it does seem to be a bit too prevalent.