I mean it can't really be bad because it's odd. Odd Warrior can't run execute so this will be welcome. Clean up things you can't finish with your weapon, Dynomatic, Rush or more than half of Dr.Boom's powers.
More flexible than execute in a way that it can kill your own minions as well, triggering your Deathrattles for example. Warriors don't really have many ways to activate their own Deathrattles (shieldslam is meh).
This is a really strong removal for tempo decks, 1 mana deal 4 is nothing to laugh at, with Ravaging Ghoul and Blood Razor to name a few, you are making a way bigger impact than Execute because 1 less mana means 1 turn earlier.
Execute is still the better option for control, but I wouldn't be surprised if odd warrior runs devastate, if non odd control warrior runs both execute and devastate, and if tempo/rush whatever aggressive warrior runs devastate over execute.
It's not very elegant from Blizzard to release a removal card for Warrior which is strictly worse than pre-nerf Execute. It's like taking ice-cream from a child, eating half of it, spitting on it, rolling it in dirt then giving it back. It's not nice.
Also giving Ferocious Howl to Druid, which is also much better than Shield Block, was not nice. Not mentioning Greater Jasper Spellstone.