I'm not 100% sure the single fan design is "dropping the ball".. There was a discussion on cooling designs I read someplace here, and a fluid dynamics engineer chimed in and said that a pull only configuration will always be more efficient than a push pull configuration. He said Fluid Dynamics Don't Lie.
A superior pull configuration only works in the case is fully sealed. The S5 is
not sealed, so a pull configuration would be horrible on it.