I think the game could be improved immensely by adding more randomness and difficulty to the dungeons. This would also slow the pace of zergs. Could be implemented as a new mode "dungeon crawl" mode.
So here are some of my suggestions:
1) A 10% exp bonus if nobody dies during the quest.
2) Randomly trapped chests, with search being able to discern trap type so groups without rogues can try and buff through a trap. For example buffing a resist energy to fire for a fire trap on the barbarian who opens it. Trapped chests should have more treasure of course then normal traps.
3) Illusion traps. Create a vertical shaft 2 stories tall with spikes/water/whatever at the bottom, and randomly place it in dungeons (rarely) with a floor illusion over the surface. The fall area should be a small area so that once seen the trap could be walked around.
Fall traps could also be used to add mini dungeons off of main dungeons that the ones who fall in must fight back to the main group through.
4) Either/OR quests. Quests which branch and you can only go one way, perhaps the branching occurs based on who first talks to the NPC and what their faction with a certain house or alignment is?
5) A Maze dungeon that is represented in a tile puzzle. The group must split up, one part staying at the tile puzzle and defending it from waves of attackers, while also adjusting the puzzle based on changes in it. The puzzle actually is the map of the dungeon the other part of the group is fighting through and they have switches too that alter the puzzle as well and thus the dungeon. This should be doable only on elite and should give a big exp and treasure bonus.
6) Cursed items that require a lore check, and a stay in a tavern to remove the curses or a high level cleric etc.
7) Chaos Shrines. Shrines using the kobald crystal graphic that were color coded. These shrines would require the sacrifice of an item to work or would only restore spell OR health but not both. Res shrines that require another party member in range to lose half their health or res but apply a debuff.
8) Much more randomness in dungeons as in dungeons that are created when you zone in. So everytime you run them its the first time.
Anyway these are some things I would like added as a dungeon crawl mode to have more Dnd flavored crawls as options and less zerging.