A solution to the problem of Raid Captains

Raid Captains are a promising idea, mainly because they can generate enormous extra (and interesting) difficulty, which can really help to generate a meaningful endgame. Unfortunately, as things stand right now, the rewards are so pitiful in comparison to the extra difficulty that there is little incentive to pick up Raid Captain banners. You could simply improve the rewards (which I do recommend -- and scale the value of the reward to the number of banners picked up), but I'm not sure that would ever make Raid Captains a good way to farm gear. I also think there is a limit to using gear as the reward -- the endgame then ends once you have the gear you like.

I have an alternative suggestion: instead of giving gear as the reward, give bragging rights (or rather a sense of accomplishment). Do this by keeping records in the game, for each level, of the number of Raid Captain banners you've picked up and beaten that level. (Make it so you can see it on the mission screen for each level.) You'll probably need to index this to difficulty level, or maybe only do it for the highest difficulty level. Then give some special cosmetic item (cape, pet, or maybe a Raid Captain banner you can wear yourself!) for when you've beaten all the levels with 3 Raid Captain banners each, and another when 4, and so on. That will give something to aspire to; you'll need multiple optimized builds to beat different levels at this difficulty, and perhaps few will beat it completely. A meaningful endgame!