I would *like* to see checkpoints where the party can start the dungeon again from that checkpoint, 1-hour time limit renewed (no speed run achievement when using a checkpoint). When players clears the dungeon, their option for start at a checkpoint will reset.
If a dungeon was designed to be longer than one hour, then the objective of a party would be to get to the next checkpoint before the time limit.
I am for rewarding players who have invested their time into clearing a dungeon. Should the time come where dungeons are extended in length to say four hours, a party of 8 to 16 clear it, and only have dark matter to show for it? Clearing the dungeon in itself would be a type of achievement. But a good chunk of people come back to a dungeon for the loot rewards and for them that incentive could be a little less aggravating (not instant gratification, but less aggravating).
When a player invests forty hours toward gaining XP, crafting, gathering, or farming materials, they have something to show for it. Some type of character advancement or financial gain. When a player invests forty hours toward primal fights or dungeons, they may not have anything to show for it. Players who get their rewards earlier or have prioritized their game time may not see a problem with the current setup (or even a scarcer setup).
In the absence of a good drop, I do believe in a guaranteed token drop. Different items, based on their rarity, may require a different amount of tokens. So if someone clears a dungeon or primal fight 140 times (equivalent of 70+ hours of investment), they shouldn't be 0/7 in their weapons or never got the loot in that dungeon, but gradually approach their goal. That they can move on to other content.
In terms of MMO progression, I would hope this chance loot concept on instanced content was a thing of the past, i.e. Everquest or FFXI. Or possibly only popular in some Korean developed MMOs. i.e. Aion.