I'm probably largely in the minority here, but I'd argue that all 5 cards are fine.
Crystal Caverns is cancerous, but it loses heavily to Aggro decks like Face Hunter and Pirate Warrior and can even lose to the more aggressively tuned mid-range decks like Jade Druid, Elemental Shaman or Midrange Hunter. Rouge's sitting at just under 50% winrate with Quest Rouge being the most popular, so I'd say that it's perfectly balanced.
Ravenous Pterrodax is essentially zoo-lock's saving grace right now. With Power Overwhelming gone, they need a cheap card that can swing tempo quickly in their favor. Can it become a 7/7? Yeah, but in almost any scenario, you wouldn't take that combination of buffs. Usually a combination of Windfury, Divine Shield, Stealth or Can't be Targeted are much more preferable.
I'm content with each class getting at least one decent non-legendary card exclusive to them. Its why I was content with Hunter's getting Unleash the Wild and why I was fine with Priest getting Dragonfire Potion. I honestly can't play devil's advocate with this one. Its got a strong effect, its got decent stats, its cheap and its a much faster card. Blizzard wants secret mage to be a thing, just be glad they didn't have to give them Ragnaros' hero power to get players to play it.
Same as above, Crackling Razormaw is a strong card and I'm content with each class getting one strong non-legendary card per expansion.
Tar Creeper is not op by any definition. If anything, its great design use of taunt. Its a cheap minion that impedes your opponents ability to deal damage to you, but it does not allow you to deal effective damage against your opponent. While Tar Lurker and Tar Lord probably have waaaayyy to much health for their costs, I feel a Sen'jin on your opponents turn and a slightly buffed Silverback Patriarch is fine.