My solutions:
Critters- While they provide no material benefit, they make the world feel more alive. The game could use more wildlife that's not monstrous (also one-shotting things is fun.)
Random Events- Place them in spots that require you to go out of your way to reach (i.e inside caves.) Would reward people for taking the time to explore a map. Have them give worthwhile result for completion (probably just XP/Green item.)
An example off the top of my head:
You travel to the end of a cave and find a glowing sword in stone and a small plaque next to it that give some blurb about a cursed hero and a warning, interacting with it spawns what would probably be a F.A.T.E.
Once completed a ghostly hero spawns and talking to said hero rewards you with a job-appropriate weapon(scaled ilvl preferably) and a 30min buff that gives something meager like 5% dmg/xp while in non-instanced areas.
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Obviously the novelty isn't permanent and it would be more or less useless to max players, but consider that having more non-instanced ways to get XP is sorely needed. Not to mention these things become more enticing once you begin to add things such as exclusive glamors or making the above events be the result of completing side-quests.
Speaking of which;
Sidequests- Probably one of the biggest factors in killing the world, they are quite bluntly just too worthless. Buff the XP by a very significant amount, make them reward items comparable to dungeon loot or at least very close to it, and it would do wonders. They should also be repeatable on alt-jobs.
There are ways to make dungeon finders more community oriented, you just have to be creative.
If it were up to me:
Each dungeon would have a leaderboard that could only be viewed at the dungeon entrance, could even be an NPC. Would show timings/total # of runs for both standard and undersized parties. Could have being in the top 3 or 10 reward a title similar to something like "Conqueror of X(dungeon name.)" Which I think would open some interesting RP-based ideas.
Each dungeon would have NPC's lined up near it that would showcase dungeon glamor based on job/armor type. Interacting with one would show the player what they would look like wearing it.
Making each dungeon have a shared shout chat, so when one person afk's you could at least talk to other groups running the same instance as well as your party members. Opt-out system included.
Some sort of system-side message that tells you if you've played with someone before when you load-in and what dungeon/job.
Commendations wouldn't be anonymous.
Examining someone would have an additional pane that showed dungeon history (last 5.)
There would have to be some tweaks to the above to make it practical for the devs/game engine, but making the game feel less robotic would alleviate a lot the "deadness" that is experienced when outside of popular hubs.