yeah this has been proposed in many forms alot, accually I have had a message that said I was hot or something when the weather announcements were still going.
I think those were just GM broadcasts, to support the drought quest.
Those messages will surely appear again from time to time, when some GM has time to do it and some special weather effects will occur, like snow storms, acid rain...
If you dig the proposals forum far enough, you notice that Martin did the broadcasts for the first time. And that was, if I recall correctly, much before the drought-quest.
I know, it's just that your words sounded as if it was a server function rather then just GM broadcast. A GM can't do this all the time, so I just wanted to say that it might be kept for special events.
i have an idea that can better emphasize weather, i saw this on a game i was playing, the water reflected nearby objects and sky, and gave a very real affect to the game.