Humpbacks' breaches are not identical. There is considerable variety, for whatever reason. Sometimes the whales have some forward way on; sometimes they simply leave the water more or less vertically. Presumably the whales have sufficient motor skills to harness their raw power and achieve whatever gymnastics they wish. Some breaches seem almost (to jaded eyes) half-hearted. Others seem the epitome of athleticism, with Olympic-quality floor exercises.
Is this a jaded display? Half-hearted? Not enough people watching?