You don't know how hard it is to come up with an original idea or an original design for your stuff, and yet, everytime you do you either have your idea stolen, or coldly criticized by other dumbforget users who completely lost their faith into their own creativity.
People complain about things being generic or unoriginal, listen it doesn't matter if something is unoriginal and generic, it just has to be fun to play with.
For example, a weapon with comical effects, such as a ridiculously kickback applied to the user or the enemy, those things add good feelings to a weapon, even if it fires bullets or whatever.
I myself love deathmatching, and I've been trying to make a new weapon pack in hope to see MORE TDM servers in Blockland, but damn, It's always the same thing, there's either 1 or 2 deathmatches and guess what? EMPTY.
And yet you see servers full of players whenever the theme is roleplaying.
The weapons you listed, "Duck Cannon", it's just what I said before, a GENERIC weapon with comical effects, that's what makes it fun, and that's what matters.
tl;dr stop complaining about genericness as long as you have fun with it