Blizzard has gone ahead and made some changes to the 2.4 Patch Notes. I’ve updated my post on the patch so you can read it in its entirety here: 2.4 Patch Notes.

Some changes to the Mages section are:

Mages

• Arcane Explosion: The damage cap for area of effect damage on this spell has been increased by approximately 50%.
• Arcane Fortitude now increases your armor by an amount equal to 100% of your Intellect, up from 50%.
• Blink, Slow, and Spellsteal have all had their mana cost reduced.
• Using low ranks of Fire Ward and Frost Ward spell will now be penalized the same way healing spells are penalized.
• Frostbite: When a frost spell is reflected back at a Mage, it is now possible for the Mage to suffer from the Frostbite effect.
• Ice Barrier: Using low ranks of this spell will now be penalized the same way healing spells are penalized.
• Icy Veins no longer stacks with Bloodlust/Heroism.
• Improved FireWard has become Molten Shields.
• New Talent: Molten Shields will cause your Fire Ward to have a 10/20% chance to reflect Fire spells while active. In addition, your Molten Armor has a 50/100% chance to affect ranged and spell attacks.
• Permafrost: This talent will now correctly increase the movement slowing effect of frost Armor instead of the attack speed slow.
• Spellsteal will no longer overwrite a longer duration buff.

Comparing these to what the unconfirmed “Leaked Patch Notes“, it looks like some of the things were true.

The damage cap increase to Arcane Explosion is very nice to have. There is a buff to Arcane Fortitude that will give us like… 250 more armor or so, no big difference, but a buff nonetheless. The mana cost decrease for Blink, Spellsteal, and Slow didn’t come to us in a form of a Talent, but as a freebie so /cheer! Icy Veins not stacking with Bloodlust anymore /rasp!

The big thing that caught my eye is the new Talent for Molten Shields. It will replace Improve Fire Ward on the Fire Talent Tree. It will give 50%/100% chance that Molten Armor will affect Range and Spell Attacks. Thus, a 5% reduction to getting Critically hit by Ranged Attacks and Spells! (uh duuh!! this is already true – thanks to Shalkis for pointing this out for me >_<) This means that Molten Armor’s damage proc now effects ranged and spell damage. This also means that Impact can now proc on Hunters and casters attacking you! This however requires going 17 points into the Fire Tree, so it won’t help Frost Mages much, but it gives Fire Mages some help in the PvP field (which is needed). We may be seeing some various Frost/Fire PvP builds in the near future too. Maybe something like this: Spicytuna Frost-Fire Deluxe! or something along those lines =P

Patch 2.4 is shaping up quite nicely