RNG + tokens system

[Scar.brother.help.me]

I'm only talking about the Reward system of this event, not the event itself. I like that you can buy the parts you weren't lucky to loot from rotations. So at least your time is not wasted, it builds up slowly to the goal even if no luck. I'd love this kind of mechanic to be added to the daily grind on the starchart anywhere possible.

Let's say bosses will drop a Token (whatever funny Warframe-ish name instead) for each successful mission. Each piece of equipment will cost like 5 to 10, so if you are lucky - RNG can be a nice surprise to get an item sooner, but if not, at least you know where it ends for sure, no frustration when something just doesn't drop today.  
There are plenty of npcs who do nothing, they could tell more lore about the boss and exchange those tokens for the parts you miss from that boss. And if you have any left - you can sell them for 50k-200k (So at least there will be some less Index cred farm)

Same can be made with any other rotations where you have to farm an untradeable item with some vendor npc. At least untradeable.