I don't see any problem now in having the two options available, PVE and PVP.
Before 23, yes... since it was pretty hard sometimes to get a match since you had to wait a good amount of time to get in a game (if you have a team is another story), and if you want to reduce the waiting time, you need to put all the players in the same pool, but after 23 is supposed that the player base will grow, and with that you can offer the two options, one for the players that don't want an antagonist, and one for the players that want one.
Isn't a bad idea, in fact, can be a factor that will make the game growth. Anyway, the devs always say that the game evolves in consideration of what players want, and if a group of them want this option, the game can evolve.
And don't see this game like something that "you play as is intended to be played" since the devs told us that they listen to the feedback and react in consequence... so, isn't a bad idea the PVE and PVP option in the future.