A few thoughts:
The early days of Effect came into being when drum corps started to evolve from being merely a military activity to a creative one. Not just in terms of tossing a flag vs an honor guard. But asymmetrical drill, pit voiceings, (yes) electronics, et al. The argument back then was how to compare "demand" which was on a technical sheet vs. playing it safe and marching a block drill. So the concept of how "effective" something was, then added to give credit for those that began to think outside the box of that time. Flash forward years ahead with huge creative forces and the GE has become the driving force in judging what is now considered a "pageantry" art form.
The new sheets are an attempt to move forward, yet also gravitate back to some of the original intentions. Proficiency and Visual are looking at things from mainly the old aspect; how clean, training and well designed is the show. BUT, they are have actually added a small reference back in regarding "audience engagement" to both GE sheets. (I know DCA has also been really pushing this component with a whole subcaption devoted to connection and engagement that is separate and stands on its own.) I'm sure the intent is that shows have gotten to the point where there is so much content squeezed in - that needs to be given credit - that the audience/ entertainment factor has gotten overshadowed. You see the same equivalent being argued in figure skating and gymnastics of content vs. art. We have all seen it where there is an incredible WOW factor, but you wonder why???? So with DCI trying to really analyze how to keep both the corps growing while maintaining an audience in the stands, the new language comes into play. The trick though is how to interpret that? The wall of sound? The audience on it's feet? A dramatic theatrical moment? Most would say it is this obvious "connection" thing live at the actual event. But that could and will be argued for years. It is going to take a while for the judges to both unlearn and apply this new criteria on a consistent basis. But we need to give them credit for trying...