Asking for a refund - I not only bought this game, I bought the Darth Vader PS4 solely because of this game. I am not much of a console gamer or PC gamer otherwise, I bought this game because I'm a Star Wars nerd. They're not going to refund me the entire purchase cost of the PS4 or PSN network membership, so I'm shafted on that front. However, I like the game. I hope they improve it, yes, but it's not to the point where it's unplayable to me.
As far as 1-shotting people with the DL-44, the other day I tried my hand at the P-Cannon (you can guess what the P stands for) and I 1-shotted several people from full health. I also routinely took people from 100 to 5 health in 1 shot. Most commonly, the gun did 50% damage to people per shot, but it definitely is possible to 1-shot people with it. I felt wrong using the gun, so I stopped, but I just wanted to make sure I wasn't crazy about getting 1-shotted. Interestingly enough, that same day I tried the DL-44 experiment, I was also finally able to 1-shot melee someone. No idea how to recreate the conditions to cause an insta-death, but it can be done.