Update (10/12): 4.0.1 is being applied to US servers right now and is expected to arrive on EU servers tomorrow. Now is your last chance to prepare!
MMO-Champion bravely attempts to make a full list of all the changes being applied, check it out here. Wow Insider brings listage as well.
Update (10/11): Forgot to include the bit about the new Raid lockout system, fixed now. Also added some more blogposts (Boomkin, Hunter, Holy Pala, Healing Priests).
The first in the series of pre-expansion patches will be here soon, maybe even as early as next wednesday (13th). And now is the time for you to prepare for all the changes coming so that we can have as smooth of a transition as possible, raidingwise. Make no mistake, your class is changing fundamentally, regardless of what it might be. You will have to adjust to new rotations, new casting priorities, new resource mechanics, new talent trees, new spells, old spells changing so much they might as well be new spells, new stat values, etc, etc.
- A total revamp of talent trees for every class. You can check the new trees out on MMO-Champion.
- For every class there will be new spells, old spells altered and some spells removed. Your rotation will most likely be totally different and you’ll have to read up on the changes specific to your class. Your dps/hps might go way up or way down, prepare for a bumpy ride. I suggest spending some time with the target dummys and in some heroics before actually entering a raid.
A good example of a spell-change that affect us all is the new Rebirth, it now has a 30min cd.
- New stat values for pretty much every class, and new stat distributions on current items.
- Armor Penetration – is gone. Current ArP gems turn into Crit, ArP on gear becomes Haste or Crit.
- Agility/Strength – now gives double the AP and is as such doubly awesome. Consider going back to some old items with more pure stats like the Greatness trinket.
- Intellect – is the desired caster stat, it’s now the only way to get Spell Power.
- Spirit – The prime regen (mp5) stat, for all healers.
- Hit rating to Hit percentage has been altered, any Hit talents you have has also been removed. Prepare to regem for some Hit!
- Mastery – You won’t find it on any gear, but you can Reforge your way to some of it. This stat should be highly desirable for all classes.
- New Glyph system with no more consumable glyphs, you learn a glyph once and then you just switch around what ones you want to use currently. Also, there’s more glyph slots and new glyphs to pick from.
- Reforging – You can adjust the stat distribution on your items to fit your needs, like for example removing or adding some hit.
- Armor specialization – You’ll get +5% extra of your main stat (Agility/Strength/Intellect) if you only wear gear that you were intended to wear. So for example Warriors and Paladins with leather will need to switch gear. Same for druids with cloth, Paladins with Mail, etc.
- Testing of new Raid lockout system – They want to test out the new lockout system they’ll be using in Cataclysm. They’re giving it a soft start and making Icecrown Citadel and Ruby Sanctum have their 10man and 25man versions sharing lockout. The idea is that you should only be able to kill a boss once per week on a character. Other WotLK raids are unaffected by this change, until the release of Cataclysm.
- Gems are being altered – Like mentioned above, no more Arp. But there’s also no more AP gems and possibly more stuff that I haven’t noticed yet. Also some gems are changing color, for example Hit is now a blue stat. This means time to regem to get those socket bonuses back!
- No more emblems – Your curent Triumph and Frost emblems will turn into Justice Points, which will be the only kind of point you can earn before Cataclysm. All older emblems turn into gold. Check out the conversion calculator here. Be advised that you can go over the cap of 4000 points in 4.0.1 but once 4.0.3 hits (before the expansion) all points over the cap will be converted into gold. You cannot scam the system into awarding you free epics at lvl 85. At most, if you’ve reached the cap before you hit lvl85 you will be able to pick up 1 to 2 blue items for your points.
Furthermore, at these rates you will earn over a 1000 Justice points per week if we clear ICC25, do the weekly and the daily heroic. If you do some extra raids as well you could earn well over 2000 Justice points per week. In other words, you’ll hit the cap without any extra effort, in no time. Do not worry about it.
- New UI – Some examples here. The new UI also includes a Power Auras like procc-aid to help you use procc abilities when they become available. And, a great new default raid/party frame for healers (check it!).
- Buyable 310% speed for all flying mounts. This might just be unintended on the PTR for the moment, but right now you can actually buy this upgrade straight away in 4.0.1. So be sure to check the flight trainer once the patch hits! (costs 5000 gold). Another fun change regarding mounts is that you can mount flying mounts in no-fly zones, you just can’t fly (This was apparently a bug that has now been fixed).
- New sexy water – Look at it, so sexeh!
Some handy blogposts about the class changes on a per-class basis:
- Death Knights
- Druids – Resto, Feral (Bear) (2, 3), Feral (Cat), Moonkin (2, 3)
- Hunters (2, 3)
- Paladins – Protection, Retribution, Holy (2, 3)
- Priests – Holy/Disc (2, 3), Shadow (2)
- Shamans – Enhancement (2), Elemental, Resto
- Warlocks (2)
- Warriors (2)
Also a note about what 4.0.1 doesn’t bring since I know you will ask:
- New zones
- Revamped old world content with new quests
- Flying in Azeroth
- Worgen and Goblins
- New Class/Race combos
- Level 81 and above