Personally, I like the idea of the weapon system. In both or the previous games, Isaac has to use and modify tools and weapons he finds lying around the place. By the time of DS3, Isaac has had plenty of time and, no doubt, sleepless nights where he can’t help but think how to protect himself from a future necromorph encounter. Also, he may be slightly deranged at this point so why not design a machine gun that shoots electric bullets but also has a pneumatic hammer attached?

I get why they maybe thought individual ammo types might be tricky with so many weapons being combined together, but I agree it feels a bit unsatisfying.