Sure one-shots are going to happen. In fact, I would amend
@Ying post from "Don't get one shot" to "Don't get one shot *often*".
When you say you know how to play the game and avoid damage, are you being completely honest with yourself? Do you know how to avoid damage in R1 or in R10? I ask this question because on my inquis, I am a squishy-ish player with below average talent on the keyboard. I don't die a whole lot in R10. I get one shot occasionally, but usually have just enough HP/defense to survive a typical ranged attack. I try never to use AOE unless there is a tank or beefy melee that firmly has aggro or if it is for clean up on a pack that has already taken a lot damage (gotta swipe some kills, lol). If I am attacking a single target, I make sure I have hunts end off timer so I know the mob will be dead before they get two shots on me (the first will be deflected). When I die, it is almost always because I was not skillful enough to avoid it or because I was not paying attention (sometimes I can't see the venge circle, and sometimes I just wasn't paying enough attention, haha).
I know that my HP (about 3K in reaper), is not too far off what many good ranged players have, but the good ones are far more aggressive and still survive...I am not unhappy, they are better on the keyboard.