Ok, so to preface this, I didn't read every reply, so if someone covered it better, apologies. First, looking at your spec, you're missing the reduced CD on Obfuscate and our interrupt. Against healers in particular, but any class with a hard cast (TRACER MISSILE!!derp!11!) this talent is absolutely magical. Coupled with the reduced CD on charge, you have a 6 second interrupt with a 4 second lockout, and a 12 second interrupt/gap closer. Also, the runspeed increase to predation is something I simply won't go without, ball carrying, switching nodes, streaking ahead to open the bridge before they can muster a defense, gap closing, it simply rules. Ok, so on to combat. I saw some people mention it, but Deadly Saber is off the GCD, it should be primed WHILE you're leaping to your target. Land, Battering->Leg Slash->Rupture. This is my opening because I don't take Seeping Wounds, it's 2 points for a weaker snare that lasts like 1/3rd the duration. It's not worth it, not when you have a 1 rage, spammable, 50% snare. Ok, so now they're snared, have 3 stack of deadly and rupture running, you're in a good spot. Things to think about: if you have a 3stack and rupture running, choke that pub nub, choke+deadly+rupture is a lot of dmg to eat while CCed, and since they're not damaging you you can regen a good chunk of hp, depending on crits. With short fuse and defensive forms, if you're getting hit, you only need ~6 rage consuming abilities to get a full stack of fury. That happens FAST! Pop berserk as often as it lights up. If you can initiate combat without charging, absolutely do so! Against sages and troopers in particular, this essentially makes it your fight to lose. The only way they're getting you off them is knockback, to which you respond with charge, and now you have plenty of contact time to tear him down. My arch enemies are tank build assassins, I've found that the only way to beat them is to prevent their force lightnings/telekinetic throws from ticking the full duration. Since it is uninterruptable due to the stacking talent, you have to CC them. As soon as I see one start channeling, I choke, fight continues, he builds stacks, starts channeling, force camo, repeat, intim shout. If they aren't dead by this point, they outgear you crazy style, or have heals, and why are you 2v1ing a tank assassin with a healer in the first place. Hope this helps a little.

I'm not sure what you're expecting, but there is no minimum range or damage penalty for being too close to your target as a ranged class. You do full dps to any target from 0-30m, but, particularly in the case of the trooper as in your example, they have to be stationary, and their main attack has a cast time. If you simply allow a trooper to stand still and free cast on you, he's gonna drop heat on you, that's not how this game works. You don't gain advantage simply from being in melee range, you gain advantage from all the abilities available to you while in melee range, one of the most important ones being your interrupt. Saying, "I should be able to go toe to toe with a trooper and just spam my rotation and win, interrupts are for heals" is like saying "I should be able to beat this professional fighter just throwing wild haymakers, blocking is for sissies." Mitigating damage is just as important, if not more important, than dealing it. Preventing a 2k crit, for 1 rage, off the GCD, and removing his ability to perform his most important attack is far greater than eating that 2k crit and 2 more grav rounds that he wouldn't have been able to cast due to the lockout period of interrupt. You don't even lose dps because it's off the GCD, there is literally no reason not to interrupt.