I get where you're coming from, but we did have a game canceled this year and that messed the season up pretty bad - a dome would've changed that. Exactly how different the season goes is debatable and we'll never know, but that's a bigger argument for the dome than just not liking bad weather. Now we may never have another weather cancelation without a dome, but it has more supporters because of that.
With that being said I'm not really a fan of domes - I just think this year brings up an interesting case.