Well, since I already posted nearly everything I can think about mechanics, let’s start talking about secondary stuff, like lore, quests, expansions, etc.
At start, would be very nice we having multiples storylines, being one with global impact (Example: the Garlean Empire), one affecting only the realm (Example: A faction War that would cover Eorzea…completely unrelated to Garleans), one with regional impact (Example: Kobold pirates armada taking over the Sea of Ash as their turf) and local storylines (Example: a story happening during a tournament at Bloodsands). We saw this in FFXI (the add-ons and some quest series, like class quests and the general saga quests)…that’s mainly what I would love seeing…multiple smaller storylines walking in parallel so the player would always have something new to do…but, of course, in these cases he would be locked to one storyline at a time…just like each city story in FFXI…once you complete one set of mission you receive a exclusive reward (like the flags furniture in FFXI…not always the reward need to be uber gear like the infamous Rajas ring, that is Lv30 but people still use it at lv95 because there is nothing even to it still) and can start another one!
Would be nice small stories regarding minor lore aspects of the game, like Mistbeard, Limsa Lominsa (the plainfolk city was named under, not the city…I could even imagine some crazy stories like he being the best pirate ever seen in Hydaelyn…a pirate so crazy that the sea wasn’t enough, being then the first pirate using airships and, being so, the first pirate of Skyward realm! Also making him leave to skyward realm after marrying a goblin so they could live in peace and then now you being able to find his legacy during the story), The Heartstroke (the dagger) among many other content.
In short, instead of having many unrelated quests (they are good too…specially the repeatable ones…the original FFXIV really was missing lore content with the lack of quests…specially since they’re also a good way of new players to get used to game mechanics outside levequests), we having multiple main scenario-like quest sets.
Another aspect is the access to quests…I know the level/rank might be always the main option, just like the classes too for many of them…but we should have many other options too…like you getting a cutscene and a quest offering if you walk during a full moon night around Aleport, or having a cutscene triggered after you killed the 1000th kobold, being then kidnapped by a kobold elite team by the kobold king order and then having to do something like Chrono Trigger’s trial and prison break so, after you escape, you actually being offered a main scenario quest option to start working for kobold king in order to be free again…
Some other options would be just staying with a certain allotment for a real week or so…imagine a barbarian inviting you to an arena if you stay with over 200 STR (doesn’t matter if it’s way above the cap…it’s exactly the idea by hiding the quest requirements in aspects like this) and if you win all arena battles (and completing all quests between them) you being awarded with an axe that would unlock the barbarian class.
Another example would be you having full astral affinity (all 3 astral elements being at least 100 points higher than umbral elements) for a month and then having a vision of Ixion (can be a cutscene when you go to your house) in your dreams and then start a saga to find it!
Or having a certain weapon (maybe a common, unique/untradeable one rewarded by a random quest) that, after breaking a few times (0%), start giving strange messages after repaired (like “The sword’s blade seems to be warm, even after being at shelter for a while” or “you feel a shiver every time you draw the sword”)…and after the 7th repair the weapon’s soul turn out to reveal itself to you and tell you that for it to once again reach its full potential you need to take it to a legendary blacksmith somewhere in Mor Dhona to have it reforged by its creator.
I do think that the more bizarre the way of triggering quests, the better…because this adds the option of it catching the player unprepared! Like after you completing 10 Faction leves from Brotherhood of Broken Blade you, occasionally, instead of getting the option of returning to the aetheryte from War Wolf, you receiving a cutscene and being offered a quest.
The possibilities are uncountable! Add bizarre requirements, mix all disciplines and make it all as quest series for a long-term entertainment! ^^