Originally Posted by
VanishO2
Back to the point, you've quoted exactly it. The depleted keystone, while won't give you a chest at the end, will give you another shot at finishing the dungeon in time and recharging it to the next level, where you are elegible again to get stuff. And even tough you're aiming the weekly chest, you will still be able to get loot upgrades from the regular run as long as you're elegible for getting it. The way the loot system works now and will work in legion is that you will be able to loot something that is very high level because it will be a chance.
Unless you can only get ONE chest per week, not matter how hard was the tier you did, you'll be able to climb it and loot another weekly chest (for that tier). Otherwise the system would get weird really fast, as you'll only do it if you want to beat the ladder, but since they're not weekly, most will prefer to do it when they could get a higher lvl chest next week.
This is all diferent from how normal dungeons are or have ever been. We never had normal dungeons giving loot with the same power as raids do. They're always behind, even challenge mode bags didn't. So there are plenty of tests and feedback they need to get for it to go ok with the rest of the game and everything else they deem important (like the burnout effect in WotLK).
Part of the reason they actually give information about what they want to do for the next expansion is to gather feedback and reactions. So, yes, if they didn't think about this situation, they'll think with the feedback.