Nightfall matchmaking added to strike list page leave rewards and difficulty as is. However, as you have suggested a weekly challenge mode Nightfall with a three item choice reward that lets you choose 1 of 3 options provided(perhaps Ghost/Weapon/Armor each time let you choose which of the random rolled items you'd prefer?). Like how completing certain story parts and the vanguard quest giver would allow you to choose your prize(although the options were often crap), this would alleviate a multitude of butthurt on both sides without ruining the RNG element. Would you agree?