Yeah people seem pretty torn on sci-fi weapons. I personally don't mind them.
In all honesty, im also fine with with energy based weaponry in KF2. preferably the weapons look like prototypes made in Horzine's weapons labs and not yet been cleared for mass production.
A good example would be the Deus Ex: HR laser rifle.
A bunch of exposed parts and wires about and poor ergonomics would make the weapon look believable for a kind of a near future prototype weapon where humanity is taking it's first step onto producing a functional portable laser weapon.
For more advanced weapons like plasma or zed guns, maybe that should be seasonal event DLC content