I would still try to adventure, though a lot more carefully than I do now (so no more "I wonder if I can kill this thing boss creature alone" shenanigans) and it would seal me as dps. I already dislike getting hit, and if there was an actual danger to it? You can forget something like tanking...and having someone die on my watch as a healer would be horrible thing to bear D: I imagine duty finder would be either completely, or almost empty as running dungeons with a group you have no idea how good they are could be seriously deadly.

On the plus side, I imagine we would have a lot higher survival odds between the holy trinity, self heals and no open world PvP.