I never would expect a game has to have no PvP mode for me to be able to enjoy it, but generally I like PvE much much more than PvP, since cooperating, working together on shared goals is always more uplifting to me, than some virtual dominance or close beating against whoever. Especially asymmetric PvP seems hard to make fair/winable at all. PvE seems easier to balance, depending on if the dev wants to offer a fun experience or a tough as hell one. I guess ignoring combative players and solely focusing on people that generally see cooperative as the better more rewarding challenge might alter the whole enjoyment in general though. So that decision might actually influence the enjoyment of the attracted people more than I would expect.