The planet of Azeroth, what else are we missing?

[SoundOfGuns]

It's hard to tell. All places i know of have been named before. There are still things we have not seen yet though. For example there is a very alive old good bellow tirisfal, and there is supposed to be a high-elven "something" there. In game there is only this wiered circle of.... i think they are mushrooms, i dont remember at the very spot. High Elven went there, and pretty much all together went insane... So that is something that's just not there (yet?) while it definitely exists. But new Land? I don't know.

Though who is to say Blizzard couldn't create new land. Though so far they did not. Pandaria was always there, just not on the map but existed since WC3 at least.

[Black Rider]

The only things we have left are mostly just islands, some of which we don't know the fate of. We have quite a bit of the South Seas to discover, plus everything under the sea.

Kul Tiras - "shifted out to sea," supposed to be near Gilneas.
Tel Abim - Known for its bananas, South Seas
Broken Isles - Once known as Suramar, the hometown of Malfurion, Illidan, and Tyrande.
Kezan - May be destroyed.
Zandalar - Mostly destroyed.
Plunder Isle - Main base of the Bloodsail Buccaneers.
Darkspear Islands - Once home of the Darkspears, a Sea Witch had murlocs destroy it.
Nazjatar - Underwater empire of the Naga, near the Maelstrom.
Mak'aru - Kingdom of the makrura (lobster people), near Nazjatar.
The Rift - What's left of the Well of Eternity under the Maelstrom.
Gishan Caverns - Volcanic caverns near the Rift.
Drowned Reaches - A giant ship's graveyard under the Maelstrom.
Boiling Terrace - Volcanic ledges near the Rift.
Pillar Deep - Ledges filled with giant worms near the Rift.
Scintal Reef - A giant coral reef. Mak'aru is located inside.

It should also be noted that on every edge of Azeroth, there is a different name of a sea. That would imply that there is land separating the continent on the other side of Azeroth.

Frozen Sea - Surrounds Northrend (even the northern edge of Northrend).
Veiled Sea - North and west of Kalimdor.
Forbidding Sea - East of the Eastern Kingdoms. (The Veiled and Forbidding Seas connect, it seems?)
North Sea - Surrounds Quel'thalas (Quel'danas resides within).
Mistveil Sea - East of the Jade Forest.
Westersea - West of Townlong Steppes.
Coral Sea - Near the zone of Azshara. Zin-Azshari's ruins dwell underneath.

Good list really!
And there's also other side of Azeroth, from where ships aren't returning...

[Belisaurio]

They can put anything in the other side of Azeroth.
They've done that with Northrend (see some maps in vanilla without northrend), they've done that in MoP (see the globes in WotLK/BC without Pandaria), they changed a lot of times the continents and some places of Azeroth/BC. Remember that Deathwing had their lair in outland, behind the Dark Portal (there are some files in our outland-data that had "Deathwing lair" in their name too), so they can create another continent or another Titans Vault (that didn't existed in WC1-2 too), etc...

[Black Rider]

Curious, After we goto Argus next expac (wink) theres no more wow zones in lore to give us.Redoing old zones the expac future?
You don't think we can keep whipping continents out of thin air? (Source)

Haha, <3 GC
Endless planet and contient possibilites
http://www.wowpedia.org/Great_Dark_Beyond