They are exactly the same thing, Super Shotgun and SSG should be aliases. I don't see the distinction here.

Isn't the Super Shotgun..well...super?

A Super shotgun has always been a double barreled shotgun. It's always been the nickname or name for a double barreled shotgun which outputs from two barrels a slightly bigger load than the single barrel shotgun with a sawed off's precision.

Yes, it is a type of double-barreled shotgun but the article refers to a specific weapon from the Doom and Quake games. It's like we have an object page for gun but that doesn't necessarily mean we should merge every page on guns with that page.

The Super Shotgun in TFC isn't a double-barreled shotgun.