I figure this would be a useful discussion topic to have here. I'll start it off by quoting a post I made that has my opinions on what are the best new features of XIV so far.

1) Not using PlayOnline!
This was arguably one of the worst problems with the first one. I was such a ****ing pain just to sign up and register. It takes a while to even figure out how to get into the game. It's a big deal that this is gone, and it's going to help the game a whole lot.

2) Easy to solo!
This again, as you know if you've played Final Fantasy XI, is a much needed. In XI, you'd have to wait for hours and hours to get a party, and even longer to get an ideal one. You couldn't really solo in that game, and you were wasting so much time because of it. Now, they're saying you'll be able to play for 40 minutes, a few hours, or all day. Alone, or with a party. I'm glad they did this, because this is what inevitably drove me away from getting through all of XI.

3) Releasing worldwide!
Everyone in the world will be starting from scratch, at the same time. This means that you're not going to be running around seeing all of these JP players at level 75 because you had to wait for the release in NA and PAL. It also makes for easier parties, if you want to do that more anyway, since everyone will be starting.

4) Worldwide servers!
This is something WoW doesn't have, and it's really lame. This basically means that I, in PAL, can play with you, in NA, and our friends, in JP. So this means us at ZU who are getting it need to join the same server. I call Fenrir!

5) Servers cover all platforms!
Another thing which will no doubt be essential. I can be playing on the PS3 version, and you can be playing on the PC. It would be totally lame to have all of the previous points, but then restricted by which platform you're playing on, so I'm really glad they're doing this!

Courtesy of Slime's fine findings!

What do we know about the setting and the story?
It takes place on an all-new Final Fantasy world known as "Eorzea." Though it does share some monsters and races from Final Fantasy XI, they're not direct representations and have been altered in multiple ways that make them unique to Eorzea. The similarities in races will allow experienced FFXI players to create a new FFXIV character that looks somewhat comparable.

Does it have a direct connection to Final Fantasy XI?
In some ways, yes it does. Not only does it share the same development team as the FF11, but the game will also allow players to create a character that is similar to their current Final Fantasy XI. Square Enix has also revealed to IGN that it is currently finding a solution that will let you transfer your character's names from FFXI to FFXIV.

What is the combat system like?
The development team won't say, but it did confirm to us that... Additionally, the heavy team-play aspect of FF11 has been deemphasized, and now exploration and battle is said to be more balanced between solo and team play.

How does the leveling system work?
Square Enix is cagey about how characters advance, but it has confirmed with IGN that growth is not based on experience and that it will work on a different system entirely.

What about jobs?
Jobs will return in Final Fantasy XIV, but they will be much different than the job system present in FFXI.

How important are the weapons?
Weapons are very important and have a heavy influence on your character and how they succeed in the game world. Square Enix says to look closely at the official FFXIV logo for hints and hidden meanings about how the game will work.

What hidden meanings?
Square Enix told us that when it approached Amano to do the logo art for FFXIV, that weapons were very important and to think of the concept of a "wheel." Specifically, a wheel of adventurers that has their weapon in front of them and an exposed backside -- which leaves each adventurer to rely heavily on their comrades and their friends. Let the speculation begin.

Anything else about the weapons?
The team let slip to us that choosing weapons for specific tasks one day versus another could affect how your character develops.

Will the PlayOnline service be used for FFXIV?
No. Square Enix told us that the reason it is ditching the PlayOnline system is because it was originally meant as an all-in-one solution to house multiple content types. But as PlayOnline has offered less content over the years, the need for the next online Final Fantasy to us PO is moot. Whatever new service (if any) is used, PC and PlayStation 3 users will still be able to play with each other on the same servers, and Square Enix also confirmed with IGN that you can sign in with a universal ID on either system to pick up where you left off if you own both.

Who's Working on the Game?
It is produced by Hiromichi Tanaka (Final Fantasy I, II, III, and IX) and directed by Nobuaki Komoto (Final Fantasy IX, XI), with art direction by Akihiko Yoshida (Vagrant Story, Final Fantasy XII) and a musical score from Nobuo Uematsu (Most Final Fantasies ever). Yo****aka Amano has designed the logo and is pulling additional art duties as well.

Uematsu only did a few tracks in FFXI, how much is he doing for XIV?
Square Enix revealed to IGN that Uematsu will be doing all the music for Final Fantasy XIV and that it will be composed in a range of different styles and genres.

Are Chocobos back?
Yes, they will return. But Square Enix has told IGN that it is looking at using them in a completely different way than they were used in Final Fantasy XI (where they were used as riding steeds).[/QUOTE]

Also, some details gleaned from this article, though most of them are summed up in the IGN one:

-There will be no levels or experience points
-The game features a very different Job system
-Weapons are the focus of character growth
-Eorzea is the name of a continent in the world of "ハイデリン" (Haiderin/Hadelin?)
-The world has a high level of technology
-Item synthesis will still be a factor
-The concepts of time and seasons will be present
-Nobuo Uematsu is doing the entire soundtrack by himself
-Tarutaru are smaller
-The Galka won't have tails in this world
-The names of the races may change
-They expect the PC specs to be pretty high

So, most importantly: No experience! No levels! Weapons!

Guys, I know this looks like a wall of ****, but it's worth at least scanning over to find the points that interest you. This is turning out to be amazing!