Couple of things I'm going to say here:
1) What Pak's goal is with the "Storm" ongoing is to make Storm the Marvel equivalent of DC's Superman. Essentially, in her solo title, she's going to be going around the globe stopping natural disasters, toppling corrupt governments and fighting for the underdog where she sees them. In doing so, she's going to foster good will between mutants and humans with her actions. He states in interviews, "How can you hate mutants when you have superhero going around doing what Storm is going to be doing in her book?"
2) Regarding Storm's power levels, it really depends on who is writing her. Storm, from her beginnings, has the potential to wield limitless power. Under Claremont, her power was limited only by the force of her will/spirit and strength of her body. As a matter of fact, in just about all of her handbook entries, this is stated. Given Storm has the strength of will and spirit to house the essence of Eternity (a feat that would kill even the Silver Surfer) and a TON of other feats she has demonstrating an "indomitable will" combined with her potential to transcend her human body into an actual goddess, there is essentially no limits to her power. When given her full credit and not written down, the only thing that is limiting her power is her human flesh and blood form. Not only does the "Roguestorm" arc prove that Storm will transcend her humanity, but the "Twelve" story arc also shows this. It was revealed in that arc that Storm will potentially go through many evolutions shedding one evolution form after another. When all the other X-Men are old and all, if Storm reaches this potential, she would still be a young-looking elemental being/goddess. Keep in mind that her abilities enable her to perceive stars, planets and empty space as patterns of energy and forces she can bend to her will. Now, imagine an evolved Storm being able to do this with no limits whatsoever to her power IF she works towards her full potential. Just because she has the potential to evolve doesn't mean that its something she will necessarily want to develop, though. She has the ability to power herself up by drawing upon the life force of heavenly bodies. We saw a regular, non-full potential Storm use this ability to summon the full power of an entire galactic core (millions of stars and planets crammed into a relatively small space). In the galactic core story, she became a star that was the sum of millions of stars and planets. She has been able to wield energy on a powerful enough scale to defeat the Trion in their own home dimension. The Trion were three supreme beings that were the forces of an entire reality personified. They were the sum of that entire realities past, present and future. They were the gods of that dimension, yet Storm's power were able to adapt to control those same forces when she was taken to that dimension and we got to see how insanely powerful she was in that fight. She rarely cuts up like this and we aren't even talking a full potential Storm, yet look at her feats already!
The Roguestorm story is a complete parallel between Roguestorm and Dark Phoenix. Both characters had evolved beyond all comprehension, both had the near-infinite power, etc. Claremont touched up on Storm's ability to transcend humanity in an issue of "X-Treme X-Men" when she told Thunderbird 3 that she was "not a goddess yet, but had the potential within her to transcend her humanity."
When Claremont gave Jean Grey the Phoenix Force, he did so to boost her powers to Storm's levels. He stated on comixfan that back in the day, Storm and Phoenix Force Jean Grey were essentially equal in power and, in his mind, held each other in check. Difference is, with Jean, that power went out of control and she became Dark Phoenix. We all know what happened to her, then. Even going back to earlier interviews from the late 70s show that Claremont saw the two women, Storm and Phoenix Force Jean Grey, as pretty much equal in terms of power. I can repost one of those interviews here. Even in terms of feats, we saw this. When Phoenix fought Firelord, she battled him with blasts backed by the power of stars. A few issues earlier, when Storm fought a sentinel in space, she attacked said sentinel with a solar wind attack backed by the full power of a star. Storm would at times be written more powerfully than Phoenix in a story and sometimes Phoenix moreso than Storm. Both women's power levels would be adjusted to fit the needs of the story in the writer's mind. What comes to mind here is circa Uncanny 113 where the X-Men battled Magneto. Storm was written more powerfully than Phoenix in that story as she, Storm, was the only X-Man written with the power levels to defeat Magneto in that story arc. The only reason she lost to Magneto is because she held back. Phoenix, on the other hand, lost to Magneto flat out because she didn't quite have enough power to win. Phoenix's powers were scaled down in this story to rival those of Xavier's. On the other hand, when the team battled Firelord in an earlier issue, Phoenix was written in that story more powerfully than Storm.
One of the things that has me really excited about Pak writing the "Storm" book is states in interviews flatly that Storm is the most powerful female character in the MU with the power to go toe-to-toe with any of Marvel's big guns. From what has been put out, he intends to pit Storm against gods, mutants and regular humans. The editor of the book, Daniel Ketchum, told Pak to write a list of big feats that he, Pak, would like to see Storm do with her powers so they can try and fit them in the stories. This book has been Pak's dream to write for YEARS and he has not been shy in letting Marvel know this over the years either. Ketchum, by all accounts, is also a HUGE Storm-obsessed fan. Pak wants to make Storm THE iconic superhero of Marvel Comics. I think this is AWESOME, not only as a huge Storm fan myself, but to see a Black character elevated to this stature is wonderful! I'm rooting for Pak to be successful in his endeavors with this book.
