Thrill of Battle causes you to receive bigger Stoneskins and Lustrates, but not bigger flat heals or regens. The Stoneskins work similar to a PLD popping a defensive CD, but Thrill is the only CD that can give you "bigger" Lustrates due to the increase in flat HP. Combining this with Convalescence results in a really powerful healing effect, especially since they both sit on the same CD. Later on down the road you'll receive Vengeance, which also sits on a 120s CD. This means you can use Thrill + Conv, then a minute later use Vengeance, then a minute after that Thrill + Conv will be back up, etc. etc. This works really well in conjunction with Inner Beast and is basically the structure of WAR CD usage.