Every dungeon in the game is pretty much end-game, there's the story mode which follows the base level t which is appears on and then it has exploratory paths which is max level content.
Dungeons reward tokens which can be traded for dungeon themed Exotic Gear, you get bonus tokens daily if you clear it, plus good amount of gold per exploratory path.
In FFXIV dungeons are useless, only two lvl60 dungeons are relevant, the Expert Roulette ones, the other lvl60 dungeons give absolutely no reason to do them, only if people want esoterics, however there's much better ways to farm esoterics.
When 3.0 came it killed all 2.x dungeons, they didn't give exp either and absolutely no reason to do them.
Dungeons in FFXIV give useless ilvl gear, 5 ilvl bellow crafted, people would have a hard time clearing A8S in i215.
What could be done in lvl60 dungeons to make them relevant, well with Vertical progression is hard, however they could give a decent amount of gil per daily clear of the dungeons so people would do them, more variety in queues and lower queues.
Dungeons could also give tokens similar to what they did with Savage and remove the drops from them, maybe introduced crafting materials as drops instead, this way people could get the glamours they wanted and would have to run the dungeons X times to get the tokens to be able to get the gear.
World Bosses, there's a lot of world bosses in GW2, and unlike S hunts in FFXIV people have objectives to complete, it's not just spam skills to burst it down, a lot of people even with a lot of exp still go down in GW2 world bosses sometimes.
World bosses give a chest at the end, the chest contains few rare pieces, which are a tier bellow Exotic, while not relevant they can be salvaged to a rare crafting material, the chest also has a chance t exotic and Ascended gear themed after that world boss and also a very very low chance t a Precursor, which is a weapon needed to craft the most powerful weapons in the game, which re the highest tier and called Legendaries, each weapon type has it's own precursor, if bought from the market board they're very expensive, let alone buying the legendary from the market board.
World bosses appear daily at specific times, multiple times a day to give everyone a chance at their loot, the hardest ones require Voice Communication through TS to beat.
We don't have world bosses in FFXIV, the closest thing is S hunts which give ueless rewards that can be surpassed by doing 3 A Hunts.
As for Legendary weapons in GW2 they take months to get, and are still the best weapons, unlike relics in FFXIV that should also have been the most powerful, they're pretty much useless, they should just make them available from 3.2, like this i240 Relic comes out 3 months later, and will be useless in 3 months later.
This is one of the issues with vertical progression, nothing lasts.
I could write about exploration, WvW and PvP in GW2, but i'll skip for now.
But basically people get rewarded for doing anything in GW2 and gear that was available at launch is still relevant now.