Hrm. I'll say off the top that 3400 on KT doesn't suck as melee. WWS isn't showing any Mind Freeze casts but that may be a reporting problem, but honestly there's too much variation as melee on KT as a melee: did you get shadow fissured repeatedly (it happens), did you get hit with a frost tomb, did you get MC'd, was KT moving from tank re-adjustments and / or threat drops... it's one of the worst fights for RNG melee penalties honestly.
Your gear is mostly fine, sloppy enchant on the Chest and definitely swap out that Crit Strike Dragon Eye for the +27 strength one instead. Minor details that can be fixed with a day of effort and minimal time and gold investment. Hodir, Hodir, Hodir! Get to those dailies
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From my own testing Diseaseless blows the doors off any disease-based rotation. It also scales better with raid buffs in my experience, but I have somewhat better gear and Awareness and my 2xOB, 2xHS rotation does very well as a result.
The leg choice is fine, and while I haven't had them drop I suspect it obviates the 4 pc bonus since death coil is last on my priority list for strikes, if my rotation overcaps RP so be it. That said, you should test both.
Bracers can be upgraded, starter sigil (though w/o Awareness this is the one that you should be using), Mirror isn't a great choice (Fury, Greatness, Bandits, Loethebs, other?) but luck of the drops trumps all. It took me 2.5 months for Betrayer to finally drop for me. Helm from Sarth 3D is also best in slot, if you don't have the 4 pc bonus, drop the helm for it to keep the 2 piece.