I think what he means by weather will have major impressions in the future is...
Sandstorm is occuring in Thanalan, and there is a large scale besiege-like event happens with empire/beastman tribes marching to the city and they are using the weather to cover their movements. Such so that you can not see them in the feild/their number's in a distance and the movement patterns they are using to come to the city and you have to run around "blind" to find them. I could be wrong, definately speculating. I think that is what they mean by weather will be very important in the future. If you could just turn off the weather you would see people going, "Oh I turned off the weather effects and they are flanking us from the west!!! Everyone go west, we need to stop them before they reach the city!!!"
Now if my instance is the case.... I don't see why "normal weather effects" cant be turned off, and when an event like this goes on it over rides the toggle for the time of the event... but I would like my idea for what he meant, could you imagine a siege is about to happen you are running through Thanalan in the sand storm and a Cerberus like monster rears it's head out of the sand storm at you and attacks but you couldn't see it 50 steps before but at that point it has aggroed you and you have to run away, or die a warrior's death!
EDIT: also Zenaku.... recently your posts have started giving me migrane's like you post full of rage mindset and not actually think about what you are posting.... just a bunch of non thought out hate.... not saying some is not needed with the things going on... but you just have become super bitter before things have been resolved....