That example is funny. Very, very funny. Because Storm is actually on the plotting post. There is a small thread there where the omission of Ganon's weather control is acknowledged, and he very civilly already allowed her to do the one weather-related thing she asked to:

http://lucetiooc.dreamwidth.org/451784.html?thread=5443272#cmt5443272

I'm pretty sure the only limit on weather control is that they can't dictate the overall weather for all of Luceti. Storm and Saori have both been shown to control the weather in just their immediate surroundings in the past without any Masamunes swooping in to tell them they can't "what she's known for".