I believe I am quoting a rep when I say this:
Pollard in the past few years has been going bigger with his tricks, and he found that with such a wide ski, it had so much float, that even in deeeep pow, it was causing harsh impacts with some of the bigger drops/airs they are doing. So he downsized the dimensions so the ski could sink a little bit on impact. This is also the reason the ski is stiffer. With bigger jumps, and a softer ski, yougotta land pretty spot on. So you have a bigger margin of error for landing with a stiffer ski. And honestly, I had the EPs last year, and I think I only needed a ski that fat for one day, and it was indeed epic. I do however, love the extremely playful nature of the original EP Pro. It turns any and all pow pow into a playground.
Hope that answers your question!