that's why it's an exotic..

the only reason why it's an exotic is to piss people off when they see the name, believe me.
and why would you compare rocket launchers and primary weapons when it's an exotic fusion rifle?
all of the comparisons you listed are just the plain old trials of Osiris "hey i need to go flawless" guns. because if you've ever played trials of Osiris, the only weapons you see are the same TLW, Thorn, Hawkmoon, Gjallarhorn, etc. that's why i typically hate PvP rather than PvE.

The main reason I listed this because I had only just flawlessed with TLW.
My point was being that Plan C isn't a bad weapon by itself. If it was the only exotic in the game, I'd take it nine times out of ten. But there are other exotics, and most of them, even the garbage ones, do better. But I'm not just singling Plan C out for being bad. MIDA Multi-tool, Dragon's Breath, Monte Carlo, Fate of All Fools, that one Crota exotic fusion rifle, all of the which are bad for their own reasons. (Fate of all Fools is dope, but it's upgrades don't work right now due to it being exclusive. I still felt happy when killed with it in PvP though.) My main point is when they're on their own, they're very good weapons, and would replace a lot of my legendaries, yet there are many other, better exotic weapons in Destiny's current meta.