Path of the Titans is gone
The whole Path of the Titans idea has been removed from the game. It will no longer rely on Archeology or on any kind of PvE/PvP progression and instead Blizzard will just introduce a new type of glyphs: Medium Glyphs.

Medium Glyphs will add a "fun factor" to abilities, and it wouldn't be surprising to see something similar to the Fortification or Breakthrough glyphs first previewed during Blizzcon 2009. (But probably not these exact glyphs, a lot of stuff happened since last year)

Guild Talents are gone
The guild talents are gone and your guild now gets extra bonuses depending on its level. There are 25 levels and each level will automatically reward with more cool stuff. The leveling process remains unchanged and your guild will gain experience through PvP, Dungeon and Raid progression, questing, etc ...

Guild currency has also been removed and rewards will just be "unlocked" after you reach a specific level or complete a guild achievement. Once a reward is unlocked, members will be able to purchase it with gold. Some of the rewards include guild tabards, mounts, heirlooms, and it looks like you will finally be able to have a guild tabard on your mount. (Just like the Argent Tournament banners)

New members of a guild won't be able to buy everything directly, they will have to contribute to the progression of the guild before they can access the top rewards. Each time a player helps towards the leveling he will gain reputation with the guild, the best rewards will require players to be exalted with their guild before they can buy it.

Archeology will be less important
With the Path of the Titans gone, Archeology will become a "true" secondary profession and you won't really have to level it anymore. However it will still be used to let you get cosmetic/optional items, get more information on the game's lore, and ultimately it looks like we can expect rewards similar to fishing. (Nothing mandatory, but you'll be happy when you actually find something)

Information gathered from other sites:
You will find two types of items: Common Artifacts will give you more information on the lore of a race, and might be used in some kind of collection game. Rare items will give you usable items, most of them will be cosmetic but some of them will have actual effects. (Details on Wowhead)

Raids & Dungeons Split
Raid leaders will be able to split an ongoing 25-man raid into up to three 10-man raids. Those 10-man raids will be able to continue from that point on, with bosses already down.

So far it looks like it won't be possible to merge 10-man raids into 25-man raids, for obvious reasons.

Information gathered from other sites:
Raid IDs should be much more flexible. You will be able to join any raid as long as it doesn't have any bosses up that you have already killed. (Details on Wowhead)
There will be more Algalon-style encounters—ultra-hard optional bosses for hardcore players only. (Details on Wowhead)

Rated Battlegrounds
Rated battlegrounds will be available for pre-mades of 10, 15 and 25-player sizes. The amount of Conquest points rewarded will be capped so that players who enjoy both arenas and rated battlegrounds don't feel they have to prioritize one over the other.

Information gathered from other sites:
The classic Honor titles will be coming back and rewarded to the top teams each season. (Details on WoR)
The "Gladiator" equivalent teams will also receive epic ground mounts. Ground mounts because they want to reward something you can ride in the battleground and be proud of / show off. (Details on WoR)

Grim Batol Raid
The Grim Batol raid instance will be called the Bastion of Twilight, and you get to fight Cho'gall as the end boss! If you manage to defeat him in Heroic Mode, an "horrific secret will be revealed when he dies".

Information gathered from other sites:
This is an entry-level raid, just like Naxxramas in WotLK. (Details on Wowhead)
It will feature 5 bosses, and an Algalon-style optional and ultra-hard boss. (The "horrific" secret?) (Details on Wowhead)

Skywall Raid
As expected, Al'akir will be the end boss of the Skywall raid instance.

Information gathered from other sites:
Bosses will include a djinn, a storm dragon, and a lesser elemental lord. (Details on Wowhead)
You will be able to use regular flying mounts to fly from platform to platform. (Details on Wowhead)
It looks really good. Really. (Details on Wowhead)

Deepholm
Princess Therazane (yes, that's her) will be a questgiver in Deepholm, in a similar experience to the Sons of Hodir's questline in Storm Peaks.

Information gathered from other sites:
The Ogrim's Hammer has crashed in the zone and the Skybreaker is still in the air. One of the questline will require you to find out what happened. (Details on Wowhead)

Heroic Deadmines / Shadowfang Keep
Heroic versions of classic instances might not be ready for the release of Cataclysm and will be shipped in content patch instead.

Old world changes
There are a more details on old world changes, especially capital cities.

Information gathered from other sites:
Stormwind has been completely redesigned to accomodate flying mounts. The Park of Stormwind has been destroyed by Deathwing and the Dwarven District now hosts a Bank and an Auction House. (Details on Wowhead)
Orgrimmar has been redesigned as well: Garrosh is the new Warchief and is located in the center of Orgrimmar, not in the Valley of Wisdom. Goblins have their own area, the Valley of Wisdom becomes a Tauren district, and there is now a back gate leading directly into Azshara. (Details on Wowhead)

Miscellaneous Changes/Information
Wrath of the Lich King had 1000 Quests, Cataclysm has over 3000.
The current heirlooms will stop growing after level 80. There will be a whole new crop of heirlooms for Cataclysm. Goblins and Worgen will be able to start using heirlooms immediately at launch. (Details on Wowhead)

and you get to fight Cho'gall as the end boss! If you manage to defeat him in Heroic Mode, an "horrific secret will be revealed when he dies".

and won't be in Beta.

I'm still ticked they are taking my treeform and I don't get any new spells at all in the expansion. :p I like my treeform. /doesalittledance

if you buy a minor glyph. It'll just be looks though.

First of all, we’re going to change it to have three types of glyphs. Before, we had the minor glyphs, which were not really player power, and then the major glyphs, which were player power. Since they only got three choices for major glyphs, most players chose their three most powerful abilities. It’s really hard to make a situational ability compete with a main ability when you only have three choices.

So we thought that by adding more glyphs we’d give players more opportunities to make decisions. The new medium glyphs are some of the most interesting because they’ll affect abilities that you don’t use constantly but you do use, and they can be DPS or healing increases, but not necessarily straight-forward ones.

That was the first step, to break them up a little more. The second step was that glyphs are in a weird place where they’re not consumables like potions but they’re not as permanent as say, talents, either. And we know that some players walk around with stacks of glyphs that they’ll swap in and out depending on the situation. Then there was the added problem that there wasn’t really anywhere that would tell players what glyphs actually exist. So if you’ve just got your Druid to level 80 and you’re looking for some Druid glyphs, really your only options are to go to the auction house, the guild bank or a third party site and read them all.

So the new glyph UI is designed more about collecting all the glyphs for your character and storing them there. Any time you want to switch glyphs you can just use that. Glyphs are now permanent.

I read that the "extra loot" in 25-man mode would come in the form of more emblems.

Running Wild is indeed the new racial "mount" for worgen. Functionally the ability works exactly like a mount. This does mean the worgen are not bringing faction mounts to the table which other Alliance races can access. This is also of course very different from the original Plainsrunning implemented for taurens. We have no plans to try and bring that ability back in any form.

Ultimately, we feel Running Wild fits very well with the nature of the worgen race. Rather than getting a physical mount, they get down and sprint on all fours. When you're playing a worgen, it just feels awesome.

Worgens get Plainsrunning...sorry Tauren...well, not EXACTLY like plainsrunning...but still...lol

They better give us plains running back :p

That is the point, it isn't 'exactly' like Plainsrunning

Said things get added back into the game in a slightly different form, people bitch.

So the idea that a character can run fast without a mount is vastly different than the idea that a character can run fast without a mount?

Except Worgen are using a mount in pretty much every sense of the word in WoW.

You're arguing technicalities. I'm arguing aesthetics.

I could also make an argument for druids of any race getting running wild. :p

Druids got more to worry about now that their Shifted Forms no longer make them immune to Polymorph

Stupid change no matter what. Druids were unique but now like everyone else.

WoW is a PvP and a PvE game. When people complain that a change on one end affected them on another end, they're just being self-serving whiners, really. I can hardly think of one change that was made on one end that really, really broke something on the other, and yet people talk as though its this rampant thing.

If this were actually a decent pvp game, I'd be less concerned. This isn't a good PVP game, however.

I've yet to see a change made to classes in PVP because of a need in PVE. It's always the other way around. They seem to be forever changing the PVE game because of unbalances in PVP.

I've yet to see a change made to classes in PVP because of a need in PVE. It's always the other way around. They seem to be forever changing the PVE game because of unbalances in PVP.

Just because you don't like PVP or you suck at PVP doesn't mean the PVP offering isn't decent. The millions of people who play this game just to PVP don't play it because it sucks.

Just because you don't like PVP or you suck at PVP doesn't mean the PVP offering isn't decent.

there are dungeons in cata (and for that matter all expansions to date) where mobs will use polymorph.

they were the best tanks in the game while also being able to dish out damage in PVE.

Honestly it's been a while since I've played WoW, but I never understood why people that primarily PVE feel like they have anything to complain about it when it comes to PVP affecting their game.

Seriously, I hear PvE-only people whine about this *constantly* but it's not nearly the issue they make it out to be.

The locking down of the entire player base to cookie cutter talent trees purely to prevent the creative hybrid specs that have come about over time in the game simply to balance pvp does not seem comparable to me. Maybe I'm wrong and perhaps I'm wrong about the "why" they are locking down the talent trees the way they are because of my pve bias, but it seems pretty suspect to me.

Just because you don't like PVP or you suck at PVP doesn't mean the PVP offering isn't decent. The millions of people who play this game just to PVP don't play it because it sucks.

I've yet to see anyone present a better alternative...you know, maybe some other game that has a huge PvP following

Monopoly.
Go climb a wall of dick with your face.

PS. I never "bashed" WoW PVP. I laughed at your stupid comment concerning it. You're the last person on these dead forums I would ever want to talk about anything video game related with.