I have a dark/kin corruptor who's a lot of fun to play. Dark blast is pretty low damage, but the -to hit is a big help if you're building for defense. Transfusion adds to your survivability while you peck them to death. If you've never played a kin before, though, be aware that Speed Boost only lasts 2 minutes. Reapplying it can be tedious.
Here's the build I'm using right now. With Mace Mastery, you can hit the S/L/M softcaps.
Yeah I'm aware of the 'lovelyness' that is "SB PLZ!"
I'll check out your build later tonight once I get off the work computer. Thanks for the feedback.
Back in the long long ago, Kin/Dark was a popular defender build. At one point, Kin/elec, Kin/rad, and Kin/dark were almost equal in popularity. The pluses as you noted are the -tohit in dark blast, Although some cones are narrow, the +damage from kinetics leverages the cones well in dark blast.
Triumphant Defenders Forever
Psylenz FF/Psi, ArticQuark Storm/Rad, Symon BarSisyphus Bots/psn, Max VanSydow Thugs/Dk, Cyclone Symon Bots/stm, Blue Loki Ice/Cd, Widow 46526
HelinCarnate:OMG it is so terrible. I have the option to take 3 more powers but no additional slots. Boo F'ing hoo.
kinetics works best with sets that don't have cones. Cones work best when you're at range, fulcrum shift works best when you're in melee. It's not like it's a deal breaker, but how much you want to be jumping in and out of range is something to consider.
Absolutely agreeing with the prior post that kinetics and cones are a mismatch. Kinetics is more commonly seen with a targeted AoE lawnmower like Rain of Arrows, or a single target beatdown like Psi Blast, for precisely that reason.
But if someone put a gun to your head and forced you to pair kinetics with a decently damaging cone blast, Tenebrous Tentacles would be my #1 pick, followed by (Sonic) Shockwave at a distant #2. Immobilization gives you the option of hanging out within Transfusion / Transference / Fulcrum Shift / Blackstar radius without eating melee attacks. (Add ranged def and Provoke for lulz.) Getting good at jousting will be vital, to minimize time wasted moving back and forth without powers animating (the purpose of my Sonic/Fire blaster is to flip out and joust people, ALL the time).
An option is a "pure" ranged kinetic built strictly for teaming. Maybe pick up Repel and ranged defense invention set bonuses, stay 40-60' back from enemies, and play support. Definitely not the most effective kinetic build, but at least you'll be applying some blasts, mezzes, and debuffs (unlike typical "pure" empaths), and you won't need fast fingers for jousting. Think long and hard about the justification for this character -- one tiny thing you might do better than Mr. Random Fire/Kin Controller, who will otherwise deal damage, mez, and tank better than you.
Your justification will probably be "willing to buffbot for teammates not named 'Fire Imp'".
If that justification is not good enough, don't go with the "pure" ranged option. L2joust and enjoy part-time melee goodness. Then if Mr. Random Fire/Kin Controller gets uppity with you, just FulcrumShiftBlackstar the next spawn in the fase.
For the cones, you hang back and use them and go in as needed. /sonic has a cone attack, Howl, as well and yet it's rather doable.
Tenebrous Tentacles has a wide cone. Its pretty easy to encompass the whole mob..even while close 
It's a lot of fun capping your damage>nuking>transferance.
a Range IO and a Rech IO in SB can help reduce the tediousness of reapplying.
Before IO's came out I made a melee type kin/dark defender (something I read on the forums) it used Barrage and Air Superiority as the main attacks along with TT and Dark Pit..it was fun, but i died alot and deleted him at lvl 25 lol.
perma jump is ---> /up 1
Well I'm stuck at work and reading the Forum and Paragon Wiki are what I do to alleviate the soul devouring nature of work on Saturdays. So I was trying to come up with an idea for a new Character to play. I've always wanted a Kin/ but have never gotten around to rolling one up. (I hate altitis sometimes). I thought of an idea for trans-dimensional parasite (hence the siphoning powers of Kin/) and thought that /Dark would go with it the best conceptually. However; even if I have a great concept, I don't want to play something that is just a drain (pun intended). I couldn't find anything about these two combined, but I've played dark blast on defender and corruptor before so I'm familiar with that. I have my own thoughts on how these two would mesh, but would like some outside persepective.
And so, I open it up for discussion...