cross realm mythic raiding
cross realm grouping
We have had these since the final tier of Heavensward.

account unlocks galore
Mostly character-based, but that works for this game because you can play everything on one character, so it lacks context to say this game hasn't done it.

transmog(glamour) restrictions being lifted(all classes can wear all armor)
We don't have this and Yoshi-P has strongly defended not having it and how tanks should look tanky, casters should look like casters and so on. It could change now, it would just be a "why now? why not 10 years ago?" thing to me.

Sure, we have cross realm link shells and communities, but they are limited to your DC.
I have felt that cross-world FCs are a next logical step for quite some time, but when the Community Finder released, I noticed they display cross-world linkshells as if they are the cross-world FCs. It's not quite the same, but similar I guess since chat is a main aspect of FCs. You can also join cross-world linkshells on other data centers that you visit.

The truth is though, that this isn't a major issue in FFXIV. Almost every FC that exists has a discord server and because of how the majority of FFXIV players are casual, discord actually works better for them because they can communicate with their FC while playing other games or at work. The discord aspect of FFXIV is so massive that it allows many people to get alerts for events across data centers and it is just not really a major problem.

Almost the only people who actually use an FC chat instead of discord are the hardcore players, who login all the time. To get social interaction in the actual game you have to seek out and find actual hardcore players, amongst the huge sea of casual players.

We have worse flying now
I mean, it would be nice to have guild wars-like flight, but it is rare for MMORPGs to have that and it's not really a big deal. This game's main focus is instance content so changing how we fly in the open world would kinda be... a nice thing but then we'd forget about it.

give us cross data center Party Finder and cross datacenter Duty Finder and cross datacenter Free Companies.
I am actually sure that this is on their mind, especially now they are looking deeper into using cloud servers. But I think it will take them time because that's how these things are. Let's see where we are with these suggestions in the final patch of Dawntrail. We may have them already by then or they may be announced around then. Let's see.