The recent addition of the Expedition Bonus 24/7 should help with difficulty finding players for a full party. The buffs are quite substantial. It was added to help players without regular groups do the regular (non-hell) dungeons. Not sure it will help that much with the more difficult dungeons where a full party is probably more beneficial than the buffs you get for a smaller party.

Most dungeons, including hell modes, already had their difficulty reduced numerous times. I don't think GT and DMP are even that difficult as they stand right now, and Hell modes are supposed to be challenges for more advanced players.

Let me know if you have specific ideas on what to change to make them more accessable without making them too easy and I will consider it. I'm not just going to blanket reduce monster damage and defenses yet again, but if there are certain monsters or monster skills that need some adjustments I will gladly look at it.

Rewards from dungeons have been updated many times to keep them relevant to players that already collected the gear or got better gear from other sources. Moolah quests, legendary collection quests, and several new mounts added just recently to give players a reason to visit them again.

I might look over some of the armor and weapons from some of the mid-tier level 100 dungeons and make some changes to stats to reduce the curve a bit, but other than that, and what has already been done, I don't really know what changes need to happen