I managed to get it in my first solo DF, we wiped twice and got it on the 3rd try.

What bugs me about this isn't the difficulty, it's the fact that if you mess up on the dragonkillers and your DPS isn't enough, there comes a point really quickly where you know you've failed... but you still have to sit through it. There's no way to wipe and start fresh, you just have to waste 10 minutes until it resets.

That, and you can't skip the duty failed cutscene.