Obviously you agree that this is fantastic news and the correct approach to the matter. Atlanta has some of the league's best (and most rrrandom!) weather. Eighty degrees after Christmas is a thing that we must share with the nation, especially in this economy.
Sure sure, bad weather would affect attendance if we had an open-air stadium. But it's not like anybody who'd be scared off by a little cold weather was going to be contributing all that much noise anyway. Let the gods do their worst. To paraphrase the GZA, a cold-weather birds crowd would be half-big and twice-strong.
For what it's worth, we're currently building a pretty decent wintry-mix team, with a whole lot of full-beardedness along our offensive line and a consistent commitment to the power running game on every single 1st and 10. So if a high-flyin' Yankee team like, say, Green Bay came to town during an Atlanta blizzard (.5 inches of off-white mud), it might actually work in our favor.
Rich McKay puts forth Seattle's Qwest Field as a potential "benchmark" for the new stadium, which sounds perfect. As you can see here, the Q comes complete with two rooflets that
keep weather out seal in decibels. Plus it has a nice slat from which the Emerald City skyline can be seen, but our skyline is better anyway. While we wouldn't just bite Seattle's whole style with our new stadium (we'd at least paint it pink and teal), it's a nice design to keep in mind.
Oh, and the team wants to keep the stadium downtown. I have no opinion on that matter, but you might.
Edit 10:20 am: Most of you also seem to have non-football concerns as well. I'm not quite clear on this whole "non-football" thing, but thank you for your perspectives.