Patch 4.0.1 is likely to release on Tuesday October 12, although there is an extremely small chance that it will go live tomorrow. Arena Season 10 will be ending on the 12th and due to a new beta build being released over the weekend we’re more likely to see a finalized patch go live a week from now.

4.0.1 in addition to the class changes will be a drastic, potentially disastrous change for players who were planning to continue raiding until the release of Cataclysm. Although DPS for most classes is poised to explode upwards, and hit point values likewise increasing, the potency of the healing classes is being significantly downgraded. As an anecdote, my Restoration Druid on the live server has roughly twice the healing throughput of the same druid in the same gear on the Beta servers.

The healing nerfs were particularly harsh on area of effect healing classes. The result of this is that Icecrown Citadel fights that are very heavy on AoE healing fights will become much more difficult than they were before. Sindragosa is a good example of a fight that already pushes AoE healing to the limit that will require a significant number of additional healers just to be possible. Lich King heroic may become completely impossible due to the decrease in the effectiveness of Power Word: Shield – it may not even be powerful enough to block Infest at this point which would create crazy situations and might require Aura Mastery to be used on Shadow Protection Aura for every single Infest.

Blizzard hasn’t mentioned any plans to nerf the difficulty of WoTLK raids or temporarily buff abilities for the duration of Wrath. They also haven’t stated any intention to nerf the content itself like was done to Sunwell in patch 3.0.

It’s worth thinking about the difficulties and benefits posed by 4.0.1 in advance, especially if you’re in a guild trying to get a title or get that last piece of loot you want.