This is an explanation blog I made about why I personally believe the system as a whole isn't working like it's supposed to, and has made Multiplayer fall through.
Here's why I think the Supply Drop system simply fell through:
First things first, some weapons need their variants in order to be viable. In Core, an ARX-160 would be completely out of the question if the Hole Puncher and the Steel Bite didn't exist. The Obsidian Steed and Carbon are the only things keeping the BAL-27 from being an overnerfed weapon. The Third actually allows the SN6 to be recognized. They made weapons so dependable on the variants, that if you can't get the right ones, you'll nearly always be outperformed by people that have them.
Second of all, the target audience for Supply Drops are the ones in Limbo: they can play the game, but just struggle more than usual. Those are the people that should be rewarded. But unfortunately, the same odds for them are being given to either the players that don't need the variants to be good players (ie. veteran players and pro players) and the ones that are incapable of playing the game with a MP11 Goliath or a ASM1 Speakeasy. The people that actually need them fall through, and the ones that don't need them either become literally untouchable alongside their jesus-like skills or the people that simply don't play the game again and go to another game.
The rewards are, simply put, going towards players that are already good without them, not to the people that can bounce back with a taste of the Insanity or The Doctor. This whole system alone makes Advanced Warfare a bloodily unbalanced game. it's not the weapons themselves in some instances; simply the variants. The only exceptions I have to this are the ASM1 on console and the EM1 on PC.
PS: Before I sign off, there's an abundance of bad variants in Advanced Warfare as well. As much as there is good, there's still bad, like all the mobility and handling variants (peace be with you SAC3 Pain and Suffering victims), as well as variants for some weapons that are overall bad, like the Lynx or the Grach.