I've made a character using Fast Shot and using the Gatling Laser for both games. In both games, I also use single-shot weapons to conserve ammo. From what I have seen, however, the Gatling Laser's critical damage is reduced against enemies wearing anything similar to metal armor or power armor. Compared to a Minigun or a Bozar, the Gatling Laser can't get anywhere close to over 1000 points of damage when fired at point-blank range. In fact, the damage seems to vary from the triple digits to less than 100 against enemies such as Brotherhood Paladins, Enclave Soldiers, and Super Mutants wearing armor. Whereas by comparison, the damage with Minigun or Bozars can get over 1000. Must have something to do with the fact that laser damage is resisted by armor and that it doesn't fire as many rounds as a Minigun.

So I'm starting to wonder if a build focused on the use of the Gatling Laser is even worth doing anymore in the future. From what I've seen, it's a much more powerful weapon in 3 and New Vegas. What do you think?

It is weak due to the reasons you mentioned + its ammo has no modifiers. The only good thing I can think of is its Weapon Long Range Perk.

I got rid of my notes for this build since I won't be making it anymore. Burst Fire is apparently best used with Big Guns.