I think PVP could use a lot more balancing before any type of ranking system is introduced. Personally I question the design that each class is locked to a specific type of gun, but this is just my opinion. Objectively, right now certain guns perform way better than others. This is a big problem that needs to be addressed before rankings would have any real meaning. Otherwise you will just see people (ab)using the best weapons playing the same characters.
Hey, the PVP is very fun in WWZ - Do you plan on adding a ranked system to it? Would make it a lot more popular and give it more sustain long term.
No, 100% disagree, leave the game on it core.
Btw, it's to unbalanched and will ruin stats (join in the middle of a game, join in a game with 10:45 for your team... )