The fact that the Rat 5 offers vertical tilt helps, but it was not enough. That was part of the motivation behind the hornpack. We have very low failure rates on our systems and we do drive our speakers to the limits of their capabilities. One really key aspect to reaching high volumes with a reflex system is the baffle density. If you space the speakers far apart, they just don't work together, and doubling the system just sounds worse and does not get louder.
Many systems take an inherently loud box and work on fidelity issues.
When you form an array, it becomes more and more the driver and box to box interaction that determines the throw, rather than the system type. At least that has been my experience. Sometimes I will design a box based on a specific speaker that I want to implement, and sometimes I design something and wait for someone to design the component to make it a reality. The Rat L wedge is a good example. We came across the horn three years after the wedge was designed.