Dungeon difficulty needs to be re-worked to include a truly challenging, but non-timed, level of difficulty that offers relevant rewards.

Currently, we have 5 tiers of end-game dungeons:Normal Dungeons -> Heroic Dungeons -> Mythic Dungeons (LFR gear) -> Mythic Megadungeons (Normal Raid Gear) -> Mythic+ Keystones (Up to Mythic Raid Gear)What are the problems with this?The first problem is that today's heroic dungeons are not "heroic" at all. They are not hard, and they only exist to slow down gearing for new characters. The second problem is some players want challenging dungeons with good rewards but do not enjoy timed content (such as M+); they want their dungeons to be mini raids. And the third problem is that mecha-dungeons need a re-work to stay relevant to raiders.What am I proposing here?Keep Mythic+ the same as it is now.Completely re-do the current heroic dungeon system to make heroic dungeons offer the same level of difficulty, and rewards, as mythic dungeons. (Basically, re-name mythic dungeons to heroic, and make that the new heroic difficulty)Up the rewards on normal dungeons to make them the same as today's heroic dungeons.Create a new mythic dungeon difficulty that offers normal-quality raid gear. But tune them to be moderately harder than a normal raid. (Basically, turn all mythic dungeons into megadungeon-difficulty)Offer heroic-quality rewards for megadungeons on hardmode.Have all forms of dungeon content count towards the weekly chest, and offer end-of-week gear that is one-tier higher. (i.e. mythic dungeons would have heroic-raid quality gear in the weekly chest, heroic dungeons would have normal raid-quality gear... you get the picture).The new system would look like this:Normal Dungeons -> Heroic Dungeons (LFR Raid Gear) -> Mythic Dungeons (Normal Raid Gear) -> Hard Mode Megadungeons (Heroic Raid Gear) -> Mythic+ Dungeons (Up to Mythic Raid Gear)What are your thoughts on this? I just want to see a challenging form of dungeon content that has good rewards, but is untimed.