A laser shotguns is a really weird concept. (It deflects the laser beam in a "random" direction?!) A high rate of fire, low accuracy weapon would be easier to conceive of.
Beyond that, there are plasma shotguns and sniper rifles, and a variety of extra laser weapons in the "Armoury Expanded" mods that you could use (as inspiration or to tweak).
I've sat and given this a lot of thought actually. Like I said, I want to cater to a bunch of different play styles as the ultimate goal of this mod. I know it needs A LOT of tweaking for the sake of balance but I feel like I should get all the weapon concepts together first before I sit down and finalize the project.
I'm aware there's a lot of weapons available in the Alien Arsenal Expanded mod, that, combined with this mod, is what gave me the drive to take over what Rockfish abandoned. If he comes back I'll work to negotiate some kind of deal with him but until then I'll pick up where he left off. I want to make a large weapon mod that's fun to play
and makes the game more challenging. Even on superhuman, I find the game isn't challenging enough for me, so why not change it up by giving the aliens a veritable fun-house of weapons? I know some of these won't even penetrate the armour provided by the Power and Flying Suits, but that's half the fun isn't it? I need to sit down and rework the game's deployment so that as you progress further into the game the aliens have more and more powerful weapons.
As for making a "laser shotgun" you can split a laser beam irl with a prism, so why not split it with a piece of Elerium as the prism? As far as I can tell, Elerium is a [transparent] crystalline material of unknown properties, so why not use it as a splitting prism? The Thermal weapons are actually shotgun-like weapons (although I think in the most recent iteration I have them set as single projectile weapons) and they're kind of interesting with how effective they are.
Call for help:
I need help from spriters, please contact me. I've realized that my "skill" with spriting simply won't cut it for a project this massive, especially if I want to change out a large number of existing skins/sprites.