The change in the next build not only will cause damage increase, but also result in the changes of elemental runes. As for the details, you can read the original post from the community manager Nevalistis:

"While we don't have plans to innately reduce the Arcane Power of Meteor in the next build, we do have some significant Meteor changes coming in the next PTR patch that should make the Arcane Power you're spending feel much more valuable.

In addition to damage increases for the baseline Meteor skill, we're making some changes to a few of the elemental runes that weren't fully embodying their fantasy. The goal is to make each flavor of Meteor different and more indicative of its element while keeping each competitive in its own way. These changes should also make the Tal Rasha's Set bonus more appealing.

Comet has been slightly modified, dealing a great deal of Cold damage on impact and freezing Chilled enemies for 1 second. You'll still enjoy its icy mist after effect that deals additional weapon damage as cold over time and chills enemies.

Star Pact has also been redesigned, and is now a little reminiscent of the Barbarian's Ancient Spear (Boulder Toss) rune. You'll be able to expend all remaining Arcane Power for a massive amount of Arcane damage, with each point of additional Arcane Power spent granting a 20% damage increase. (I'm personally looking forward to exploding things with this!)

Lastly, Lightning Bind has been replaced with a new rune, Thunder Crash. This new rune removes the delay on Meteor, to better embody the quick nature of Lightning based spells and abilities.

We're also updating The Grand Vizier with a new Legendary power oriented around Meteor, which will now reduce the Arcane Power cost of Meteor by 45-60%. This aligns with our goals of making 2-handed weapons feel more powerful and desirable, and we'd like to hear your thoughts once you get a chance to give these new options a go!"

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