Having just done the nightfall for the 3rd time this week, I found a glitch for one of the Taken Captains after destroying Malok. I'm a little surprised this idea hasn't popped up before, or maybe it has and never gained popularity, but here's the concept:
Go to a strike. You get a random encursion. During the encursion? One of the enemies will appear different from other strikes you've been involved in. We'll call this enemy a "strike" class enemy.
Could be as important as a semi-boss fight, could be a black spindle equivalent side area you could explore and suddenly find accessible, or it could just be a heavily shielded/high health major or ultra and it's combat tactics? Fight until it's about to lose, then try and escape from you.
If you manage to beat it? Unique quest, unique item, unique reward gain (say you kill a Fallen "strike" enemy that FWC was hunting. You go turn in the item you pick up and you gain an instant level for the faction regardless of where your exp point was at).
What do you all think?