Across the board, these two changes have happened: fears cast by players will no longer increase the movement speed of the target they cast on and the gains from being critically hit have been halved for vengeance.
Death Knight: Blood spec will be seeing changes to Dancing Rune Weapon: it no longer costs Runic Power. Furthermore, Unholy DKs will see their Raise Dead cooldown reduced by 60 seconds with Master of Ghouls.
Druids are seeing a ton of changes in WoW 5.4.
In general, Innervate will now make it so that the target of the spell gains 50% of the casting Druid’s Spirit in mana every second for a period of 10 seconds.
The resto version of Wild Mushroom now only casts one. If recast, the mushroom simply moves. However, the mushroom heals for just as much as the three mushrooms previously did.
The mana cost of Wrath has been increased by 50% in World of Warcraft patch 5.4.
In terms of talents, Dream of Cenarius has been completely redesigned. It has been simplified, but its usability is going to increase. For Balance, Feral, and Guardian, the amount healed by Healing Touch goes up by 20%.
For Balance druids, Healing Touch will increase the damage bonus of their next Eclipse by 10%. For Feral druids, it causes their next Rip to deal 15% increased damage. For Guardian druids, when they crit with Mangle, it has a 20% chance to make their next Healing Touch or Rebirth instant, free, and castable in any of their forms.
For Restoration druids, it causes Wrath to deal 20% more damage. It will also cause the spell to heal friendly nearby targets for 100% of the damage done.
When Heart of the Wild is activated, it will now provide a 25% bonus to healing for Resto specs.
Mass Entanglement has lost its limit on targets that can be affected. This is a removal of a cap that was previously set at 5.
Nature’s Swiftness has been removed as a talent. It is now a spell that is learned in the Resto spec at level 30.
When Nature’s Vigil is activated in WoW 5.4, it causes spells that heal to trigger an additiona heal on a nearby ally for 25% of the amount that is healed. This is being added on top of the existing 25% healing done in the form of damage to a nearby enemy target.
Soul of the Forest is being redesigned in WoW 5.4 in order to widen its appeal to other specializations.
In WoW 5.4, if you are a Balance druid, you have an 8% chance of causing your next Astral Communion to instantly go into an Eclipse when you cast Wrath, Starfire, or Starsurge.
If you are a Guardian druid, you go down from 30% rage generated from Mangle to only 20%. However, the boon for this talent comes from the fact that this bonus also applies to Primal Fury.
If you are a Restoration druid, this talent now causes the druid to get a 100% spell haste buff (up from the original 75%) after they cast Swiftmend.
An entirely new talent will be added called Ysera’s Gift. It is the replacement for Nature’s Swiftness. When a druid casts it, it heals them for 5% of their maximum health every 5 seconds. If they are at full health, it will heal the most damaged friendly target nearby as opposed to the druid.
A new glyph is being added: Glyph of Efflorescence. It will increase the healing that is done by the spell Swiftmend by 20%. It also causes Wild Mushroom to be the spell that targets the Efflorescence healing effect instead of Swiftmend. It will last as long as the mushroom is active.
Glyph of Innervate has been changed so that when a druid casts the spell on a target other than the druid his/herself, both targets receive 60% of the total effect of the spell.
Balance druids in World of Warcraft 5.4 are seeing the following changes: Eclipse has been buffed so that it energizes the druid for 50% of the maximum mana when it is triggered (up from the original 35%), Moonkin Form is nerfed so that it will no longer reduce all damage taken by 15%, Starfire and Starsurge have been nerfed alike by increasing their mana cost by 50%.
Restoration druids in WoW 5.4 now get a new spell at level 88 called Genesis. It will target all party/raid members within a distance of 60 yards. It accelerates the casting of a druid’s Rejuvenation effects. It causes them to heal and expire at 4x the normal rate of the spell. It will cost the same exact amount of mana to cast as Rejuvenation does.
The area-of-effect healing effect done by Swiftmend is now called Efflorescence.
The capability for critical strikes has been removed from Wild Mushroom: Bloom. Only 100% (down from the original 150%) of the overhealing done by Rejuvenation will be accumulated. The overhealing bonus will no longer benefit from Naturalist or Mastery: Harmony.
There are many more class spell changes coming in WoW 5.4 PTR build 17056.