When the patch hits, expect the following:
- Gear stat changes
- Reforging - found near inscrip trainer
- New cataclysm talents
- Random earthquakes everywhere you go (and they are quite frequent)
- Random Elementals that attack the city (you have to kill them for NPC's to spawn). Guards come out with portals and you must enter portals to destroy the rift's that summon elementals. I'm not 100% sure this is being deployed on live but I think it is, something to do with the Shattering.
- Tons of new spells and skills.
- New cataclysm quests.
- People with 40k+ health pools.
- Racial changes and armor specialization etc changes. (IE. Holy paladins get +5% intellect for wearing all plate)
- People with 40k+ mana pools.
- New currencies: honor points, etc. marks gone.. etc.
- Everyone to be confused for atleast a month
- Extremely imbalanced pvp. I'm warning you.
- Glyphs completely changed. You'll always have all the glyphs with you, it's hard to explain. You'll need to use Removal Powder bought from Inscript vendor to remove glyphs and replace them.
- On that note, new glyphs.
- Tons of the new UI changes, and class functions: IE, holy power, etc.
- Hunters get Focus instead of Mana.
- No more ammo
- ICC Dodge debuff is gone.
- Warlocks no longer need soul shards.
Also, PVP is VERY, VERY imbalanced right now. Caster's run everything, melee suffer. It's only going to be like this until 85, since it's scaled for all that. Expect tons of crying on the forum, TONS.
What NOT to expect:
- Flying in Azeroth. Flying will cost 250 gold for a license available at level 60.
- New level 80+ skills.
- World changes
- Anything cataclysm related; ie goblins/worgens, new zones, etc.