Thankfully, Battle Rage has since been nerfed. It has been reduced from 3 mana to 2 mana and the text now reads:
Playing with Battle Rage
Draw a card for each damaged friendly character.
Most players don't typically need to bust out a Battle Rage early on. The nerf means that your minions have to be wounded (and not dead) in order to take advantage of it. Thankfully, your minions have multiple ways to take damage. The tried and true method is to throw them at your opponent's minions. But if your opponent has no minions, there's a few things you can do. Cruel Taskmasters can ping a friendly minion for 1 damage and provide it with a +2 bonus attack. The Injured Blademaster comes into play pre-damaged. You can Slam your own minion (an extra card). You know what else is a beauty about warriors? Think about all the different interweaving minions that play off of your minions taking damage. Just look at Armorsmith and Frothing Berserker. Lastly, if your minions aren't going to be able to go toe to toe with your opponent, drop a Commanding Shout and charge their lines to soften them up.
Playing against Battle Rage
Battle Rage by itself doesn't represent much of a threat to you. The potential threat is based on the amount of cards it can draw into. If you're engaging your opponent's minions, make sure you actually finish them off. Warriors don't many methods to refill their hand, so Battle Rage, Shield Block, and Slam play key roles in that. Starve a warrior of their cards and minions and you'll be able to choke and stifle their offense. Obviously, there isn't much you can do if your opponent chooses to damage their own characters but you don't have to make their job easier.
Warrior decks are stronger now then they were prior to the reset and Battle Rage continues to play a key role there so don't completely discount it after the nerf. It is still strong enough to help you dig into your deck and find you the cards you need to win.
Check out other previously featured cards!