It's a great card, on first glance. Unfortunately Clash of Kings is a better card in my opinion. First of all it triggers in defense as well as in offense, also when you are behind you have +1 Initiative +2 Gold +1 Reserve compared to the Rise of the Kraken. The trigger of the card is also easier to fulfill.
On paper it looks better because of the 2 Claim value, in practice it often left me alone when i needed to play catch up. I strongly recommend playing with Clash of King instead for afromentioned reasons, by the time you can trigger the Kraken card 2-3 times unopposed without needing money to build your board chances are you're already winning.