Just finished this one as a 19 deception assassin, (turned on darkness charge, let khem handle the boss, and I kited/aoe'ed the adds) and I have to agree with much of what has been posted by frustrated parties:
-It's not the difficulty, it's the leap in difficulty. The game establishes an access level, then tells you what level "you should be able to do this", and then cranks that expectation for one quest every so often. That inconsistency will cost the game subscribers.
-Throwing in a "L2P experience", of this magnitude, intending for it to be soloed, in the first 20 levels is ridiculous design in this kind of game. This kind of tuning and "you're not good enough" message-sending is bad for business.
-Not going to read the whole thread, but anyone telling folks to respec for this fight is wrong. If you have to respec for the fight, when you have (at par) 10 talent points, the fight is overtuned, or the class needs to be buffed.
-A kite-fight for the "backstab class" is just a stupid idea. Yes, I beat it, by thinking outside the box, but people choose their classes and build their characters based on "the box", and I can't fault people for wanting the game to let them play the character they built. If I wasn't as tank-experienced as I am from other games, I probably would have given up on the assassin at this point, as I am a good player, and won't tolerate a game telling me otherwise.
-I dislike "channel the force", or at least, I dislike its cooldown length. Long cooldowns of this game-changing nature are counter-fun to situations where multiple attempts are likely. If you make an attempt with this cooldown up, and you die, you have 20 mins before a feasible attempt can be made once more. CTF is an answer, but it shouldn't be.
I would not classify this quest as a level 19 quest for the average player, so the number you see is, in my opinion, wrong. That is, as I see it, Bioware's mistake, not the player's.
Good luck to those attempting this fight. Be assured that captain reasonable here feels your pain, and believes Bioware owes this quest a tweak. Do not gauge your aptitude with the game, or as a gamer, on this encounter!