I’m not sure how to feel about PvP being added, on the one hand it adds more variety, but on the other hand i don’t see myself playing this mode a crazy lot, i might play it every now and then, but i’ll be playing regular co-op the other 90% of the time.
Regarding PvP only unlocks: I bought the game as a co-op game (because it was literally only that sort of game when i bought it) and tying unlocks to this PvP mode seems a bit annoying for those who don’t want to/rarely play PvP, but those same people might want new skins/weapons for there co-op experience and can’t get them because the particular one they’re after is locked to a PvP mode. Do you see the issue with this? It’s like pay walling content, but instead of paying money, you have to pay in time by playing a game mode you might dislike, just to get a skin you want. Then again it might not matter too much to most people, but there’s bound to be some people who’ll get annoyed by this. Just thought i’d point this out.
Lastly since PvP modes are on the table now, consider adding a dungeon master/director type mode like the one that was suggested in this thread An idea for a PVP mode
I’d probably play a PvP mode like this a heck of a lot more then the L4D style one your offering and i’m sure some other people would share a similar veiw.