Things from 1.0 era that could return

[LioJen]

Not "Classic servers", but it would be nice to replay some of the more important story events from 1.x in flashbacks or something.

[CaptainLagbeard]

Yoshida was asked about 1.X servers a few years ago. His response was "Nightmare!"

I'm not saying they would need to host the servers or set them up, but considering people have reserve engineered a runnable server from the 1.23b client. However with all the NPCs handled serverside they can't populate the world with anything due to a lack of access to that data...

But if the people at Square still happened to have said data stored somewhere, and they put it out there, people could probably recreate the original FF 14 from before the end.

[Packetdancer]

Not "Classic servers", but it would be nice to replay some of the more important story events from 1.x in flashbacks or something.

To be honest, I feel like there are more character moments in 1.x that still have repercussions in 2.0 and onwards than there are major flashback-worthy story events. Yeah, there's the Calamity as a whole -- and you could argue the trial versus Nael right at the end is important -- but the major events of that are... well, the battle on the Carteneau Flats, which is preserved in the cinematic video. It's things like the nightmare you could have in the inn rooms upon awakening there, and how deeply unsettling that was, that were more affecting. Or the fact that via Echo-related shenanigans, if you started in Ul'dah you were able to be present during the Very Unfortunate Goobbue Incident that happened years prior, when Warburton was critically injured and his daughter Ascilia was orphaned. (Thus giving you Minfilia's backstory, once you realized she was Ascilia, and elaborating on why her foster parents -- and also Thancred -- had such a guilt-motivated need to protect her.)

[midnitdragoon]

The 1.0(1.23b) battle system would be nice... Or just give us the option of switching to a different battle system.

[Burmecia]

these halfmasks, to ease my superstitious twelveswood dweller's mind

[Packetdancer]

these halfmasks, to ease my superstitious twelveswood dweller's mind

*whispers* ...the greenwrath...

(Though, I'm pretty sure the model is still used for at least one other half-mask, albeit painted rather than plain willow.)

[ReynTime]

The 1.0(1.23b) battle system would be nice... Or just give us the option of switching to a different battle system.

Combat changed quite a lot between 1.0 and 1.23b though. And giving a switch option wouldn't work because the old combat was meant for a very different design for battle encounters.
For example, in 1.0 you had TWO things to manage in addition to MP: TP and Stamina. (People absolutely hated the stamina system day 1) and auto-attack didn't exist so you had to manually choose to do regular attacks. Later they removed the stamina system so you'd only have to worry about TP for certain actions.
Before the bigger combat revision the combat also involved targeting and breaking certain monsters' parts as part of a vulnerability mechanic. This was no longer the case by the time 1.23 happened.
The old combat system also assumed you could mix and match traits and actions across classes, you had less mobility (you had to sheathe your weapon to move away faster), no visible AoE markers, a lot of party buffs being kept up and a (nowhere near as well implemented as in XI) focus on coordinating actions with the party.
Even if you take away the cross-class mechanic and consider the current job design, it still wouldn't work because the 1.23b combat alone already had a slower pace designed for slower paced encounters. Action cooldowns were also longer.

[Likethewind]

The music, anima for teleporting(10 free ports a day?), character physics, levequest factions, being able to switch between AoE and single target for most spells, and the lvl 200 ants out side Ul'Dah main gate by the chokepoint heading to drybone(jkjk).

[Packetdancer]

anima for teleporting(10 free ports a day?)

NO

NO NO NO

ABSOLUTELY NOT

...I may still have some lingering trauma from running out of anima while doing stuff in the 1.x Black Shroud...

[_Pigzig]

How bad was it really