So a few quick thoughts.
First, I get that you're trying to use
Possibility Storm to cheat out huge threats like
Worldspine Wurm, but wouldn't that mean you would want a few one-drop creatures that actually help your cause? If they have to be cast, they might as well extend the game and help you get to T6 to be able to use the storm. As such, why
Legion Loyalist? Similarly, why
Nearheath Pilgrim? I'm thinking you'd much rather have things like
Cathedral Sanctifier and
Centaur Healer that will gain you life to keep you alive until T6. I get that
Fog and
Safe Passage help on this front, but each one only works once. Beyond that, I'd suggest swapping
Safe Passage for
Riot Control.
Second,
Possibility Storm almost REQUIRES you to play
Curse of Exhaustion. Simply put, this is the nastiest thing you could do to someone, as they literally will not be able to play a non-land for the remainder of the game. They can't even cast something to remove enchantments - if you can then take control of the board, you just win. So to that end, it would be fun... for you.
Third, I think it's safe to say,
Kessig Wolf Run is a bit overkill here. If you have even any remote inklings that you're going to have color fixing issues, you can easily drop them.
Lastly, I'm trying to think if there really are any quality options that would help reduce the randomness in
Possibility Storm given your colors... sadly nothing is coming to mind that's standard legal. I'll think on this one a bit more and will get back to you.