I would take OP's "I hover around a 2.0 K/D" with a grain of salt. Generally when people use that kind of language they mean that every once in a while they'll have a game where they go above a two, but most of the time they go slightly over even.

Let me put it this way - I have a 2.3 K/D (actual K/D), but I know that that's mostly from stomping randoms in rumble and Control. I queued into Invigorate the other night in Trials and my team lost 5-2. I was running with really good pub stompers - guys who regularly go 8.0, 10.0, Unbroken, etc., in vanilla Control - and we were sweating our nuts off trying to get kills. Callouts, elaborate strategies, everything. We had to get lucky to win the two points we did.

This is interesting. I'm usually hovering just above a 2.0; I don't do as well in Trials (1.91 currently), but with a half-decent team I haven't had any problem going flawless every single weekend playing with a 1.1 and his sub-1.0 friends. When I play with other higher level players we usually can do it with our eyes closed except for the occasional exceptional team we have to bring our A game to beat.

I think a main difference though is I've got that 2.0 with a Titan, not a Hunter or Warlock. Titans are at a pretty severe disadvantage ability-wise and super-wise compared to the other two classes, so even if you're pubstomping, if you want to do well, you have to learn how to play very technically and get a good balance between aggression and hanging back. There's absolutely no forgiveness for sloppy play, and you don't get piles of free multikills from your supers like Hunters do (if I get three kills with my Fist of Havoc it was a great super use; if I don't get three kills with my Golden Gun when I play my Hunter, I feel like it was a poor super use).