Challenge cards are quite a good concept, to me it's reminiscent of unreal tournament modifiers and halo skulls. If utilised properly could add a lot of replay value to d game and could work in theory like world tiers do in the Division. However this is all based on us being able to replay all campaign missions and adventures (not just mercury adventures) at a higher light level. Tbh i still can't believe this isn't a thing! Even if it's not for end game loot, can we please have access to the game we paid for? But I digress, this could be the first step in giving us more customization options. I played D2 for the first time in ages (and i was over levelled at 312) attempting the NF solo and i forgot how much more engaging the game is when there's challenge and you actually have to respect the enemies, without being forced to fly by (well as much as pre patch NF).