You'll get there. I have all the armour (multiple sets) and pretty much all the guns(still chasing the black hammer). Dismantled what must have been my 10th abyss defiant tonight. You will have runs where you get just shards or energy - but that won't happen every time. Just keep running it. The stuff will drop eventually. Word of advice if you can run normal then hard with crota. You might get double drops on hard but different weapons drop on each mode.