If someone wanted a more "machine gun"-esque weapon, we could easily have drum magazines for Assault Rifles, including completely nonsensical mods to make them function however you like.
Problem is: Adding new items with actually different looks to the game is a lot of work, and will only be done if it adds something to the experience.
Let's take, f.Ex., a grenade launcher. It would probably require a "heavy weapons" skill of sorts, but let's ignore that for now.
There's two options:
A) It's completely OP.
B) It's Ammo is so scarce or expensive that it's barely ever used.
B of course doesn't exclude A.
However, I can for the life of me not think of any way this would actually open up new play styles.
Whether you spend points on some new weapon skill or on throwing or pyrokinetics doesn't make a difference when the points expenditure and result are the same.
Of course, if you just more options without spending the points, then.... no.