From an official forum post.

Razormane Battleguard

Old: 2 Attack, 3 Health → New: 2 Attack, 2 Health

Arcanist Dawngrasp (Mage Questline final reward)

Old: Battlecry: For the rest of the game, you have Spell Damage 3. → New: For the rest of the game, you have Spell Damage 2.

Garrote

Old: Deal 2 damage to the enemy hero. Shuffle 3 Bleeds into your deck that deal 2 more when drawn. → New: Deal 2 damage to the enemy hero. Shuffle 2 Bleeds into your deck that deal 2 more when drawn.

Renew

Old: [Costs 2] → New: [Costs 1]

The first three cards will be eligible for the normal full-dust refund for two weeks following the patch. Renew, which will go up in power level, will not get a dust refund. Keep an eye out for Patch Notes early next week for dev comments on these balance changes and more.

EDIT: Little bonus for people opening this thread later/again; Gallon put out some tweets laying out their reasoning.

"Garrote: A fairly soft nerf to one of the better decks at high levels of play, this now requires 3 spell damage, up from 2, if you want to deal 30 from hand. Also opens up Armor gain to be more effective of a counter."

"Arcanist Dawngrasp: Mainly a change looked at opening up more room for slower strategies in the meta. Razormane Battleguard: Going down a health here will allow for more early game answers for the opponent. A fairly soft change to Taunt druid, and we’ll continue to monitor"

"Taunt druid to see if any other changes will be needed. Renew: Slower Priest decks are underperforming compared to the rest of the field, and reverting this nerf should add a bit more power back to those strategies."