Try stamina dragonknight.

You can't not pay attention to your health, not on any build. This is just something you have to learn until keeping an eye on it becomes second nature and you don't even notice you're doing it anymore. You have to watch your buffs and, if they run out, you have to regroup, e.g. find some time gap in the combat where you are momentarily safe to reapply multiple buffs, as needed. This can mean line-of-sighting, being on the move, retreating to within your group, or being aware of your opponent's rythm, e.g. have they just spent their ultimate or are they buffing themselves.

I've seen more than one request from "aggressive" players recently and I am genuinely wondering what that means. Every PvPer who wants to kill another must be aggressive at one point or another. There is no such thing as not being aggressive. Crimson Twilight or Harbinger will only kill inexperienced opponents on their own. In a duel the time to be aggressive may simply be the period while you are fully buffed. In general you have to learn how much aggression you can get away with and use that to the fullest extent. It's like high-end PvE, though. Without experience too much aggression just gets you killed. Ideally you have to be aware of your opponents rythm in a duel. Are they CC immune? Do they have ultimate? A DK that has ultimate is especially dangerous, because they don't rely on burst combos as such (other than leap into executioner) making them less predictable than, say, wardens.

My own build preference is for opportunistic builds and I wonder whether this is what you're really looking for. I dislike having to apply more than 3 buffs (ideally just two) and like my remaining skills to be situational. Such builds do not require prolonged buff rotations nor complex attack combos and they are, therefore, always ready to attack and take advantage of a situation, rather than having to be patient, line-of-sight, ambush or perhaps lure people into a fight on favorable terrain. I like simple, straightforward skills, such as spammables, gap closers, executes and reactive defensive skills, such as burst heals, Streak / Ball of Lightning and Shadowy Disguise. Nightblades and templars are probably the most straightfoward in this regard. Stam DK is a bit buff heavy, but Take Flight is a fantastic ultimate. Stamsorcs are great. Magsorc probably OK too (I've just played them less). I dislike the new classes, even though their stamina variants are meta.

If you want to be successful at the highest level, you have to get familiar with ways of generating burst. Take any stamina class, other than nightblade, and it probably means some combo involving Dizzying Swing and the Vateshran 2H. Crystal Weapon or Blastbones or Subterranean into Dizzying Swing, a Vateshran medium attack and an ultimate or execute will probably do the trick. On the other hand, if you are NOT playing at the highest level, you have other options, and by this I mean low MMR BGs. Low MMR means low match-making-ranking, because you haven't played many battlegrounds yet. In that case you may be interested in my stamsorc. I use a Master's 2H Brawler build. This build is not technically tanky, but the Brawler shield works exceedingly well while you have the sustain to keep swinging. Even when you don't hit anyone, you gain a small shield. The playstyle is aggressive. Constant Brawler spam is part of the plan, otherwise you die.

Buff up with Dark Deal (for the ongoing sustain), Crit Surge and Hurricane. Vigor as you leave the back bar, then hit someone with Venom Arrow / Poison Injection, bar swap and spam Brawler. Not bursty and won't kill good players, but you'd be surprised how well the sustained pressure and 2H Master's weapon scaling works in low MMR BGs and how tanky it makes you. Dawnbreaker + Executioner to finish. Build is in video description. This kind of build is, perhaps, a stepping stone in the grand scheme of things. It won't work everywhere, but look just how well it works in that BG.

The last tip is that you really have to watch your buffs on stamsorc, especially Crit Surge. It's the combination of the Brawler shield and Crit Surge that makes you tanky. Crit Surge lasts longer than other buffs, but I tend to get quite fidgety when any of them run out. That's why you see me streak away sometimes, even when I could, perhaps, still press for an advantage. Ball of Lightning is the stronger defensive morph, but in the video I use Streak.

https://www.youtube.com/watch?v=VniS3OdmC6k