The plans we have - and none are yet set in stone (we are looking at hiring an accountant to help advise us on how to best structure things) - are for it to be F2P. We also intend to avoid P2W that forces people to spend money to win.
The things sold in the c-store directly, which you will be unable to get without Stars (our real-money-bought currency), will largely be quality of life and personalization and vanity items. We are still debating where precisely the line will be drawn: there might be content or classifications or specializations or the like in the c-store, or there might not; if they are, they won't be "required" things you must have to be able to "win." They are options and more experiences to enjoy. Skins for powers, certain costume pieces, base items that have special looks or are premium collectables...these will be in the c-store.
Enhancements, one-shots, perks and boosts that make you just plain better in gameplay terms? These things will be gatherable through play. In-game currency will buy them from vendors, or they'll be drops or mission rewards.
If you have bad luck or lack the time or other means to acquire these drops and such by doing the missions or hunting the foes that have them, the Auction House will still exist. Those who have extras can put them up for sale there, and you can buy them.
The way we enable true F2P experience for every single thing in the game - even stuff locked in the c-store - is also through the AH. If you are one of those who has extra stuff that you don't need that you wish to sale on the AH, you can sell it for in-game currency...or for Stars. Those Stars come from other players, who either earned them the same way or who bought them from MWM. Thus, players who lack the ability or patience to play hard enough to win sufficient in-game currency to buy it on the AH, or to win the "drops" directly, can spend real money to buy Stars and use those Stars on the AH to buy those items.
They are thus "P2W," but rather than harm the game and devalue other players' efforts by buying what others win "the hard way" from the c-store, the things these players "pay to win" for were earned, by somebody, "the hard way." That somebody is rewarded for his efforts with Stars, which he can use in the c-store.
Thus, those with more money than time can experience "winning" the game by whatever definition they have, and in the process they subsidize the gameplay of those who have more time than money, empowering them to experience the full breadth of the game and everything it has to offer. The money that would be spent on third-party gold trading or paying for leveling up characters - practices which hurt the game and damage the security of participants and open people up to fraud and are thus banned by ToU in most games - instead goes to support the game, and the players all help each other get the most out of it. Meanwhile, the incentive to break secure systems by sharing passwords and account info is diminished because there are legitimate ways to get what everybody wants.
In short, we hope to harness the goals of traditionally problem behaviors to turn them to advantages for all participants in the game. We want the "pay to win" crowd, who will always be around, to empower the "free to play" crowd getting the most out of their gaming experience, and vice-versa.
Again, this is largely up in the air. There are potential issues we need to tackle with professional accounting and possibly tax help. We will test it as extensively as we can to make sure it doesn't have game-breaking unforeseen consequences. And we're aware it will take significant discipline on our part to adhere to the philosophy if keeping it from "forcing" people to pay to win. But I, at least, think this approach will harness and channel player behaviors and turn liabilities into assets for all involved.