If they include Kaladesh in the new format there will be five sets it will be joining since it rotated. It’s possoble that with these sets the energy shell won’t be as powerful as it was in standard and because the shell is so specific to the sets mechanic it’s unlikely it picks up much new in sets going forward. We will obviously know more once we know the cards in the next thee sets but it’s possible it is just a tier 1 deck instead of the tier 0 it was before.You still need to ban out the core energy combo that caused Emrakul (part way), Marvel, and Felidar Guardian to get banned in the first place. It was clearly proven that the combo was just a great shell of extra value that you could slot ANY color win conditions into. It was flexible and also just powerful enough to add on a certain percentage of free wins every now and then.
With a few years of additions to the format, the power of that shell would level out to the rest of the format. But at the beginning, it would just dominate. Like it did in standard.