As an advocate of an outdoor stadium I'm not convinced a roof makes it more of a year round facility than no roof. It's already used for football in December and theoretically January if the bills ever win the division again, and by the end of March the weather is nice again. How many events are you really going to miss out on in February and a couple weeks of March? Even then you could probably pull off seasonally themed events like a winter fest that would draw decent attendance if you really needed to. An outdoor stadium with a wide enough playing surface could host professional soccer and lacrosse during the spring and summer, not to mention events like festivals, boat and RV shows, and monster truck shows.
Wasn't the stadium cleared out by game time Monday anyway? I think they could have played there Monday this time around, the problem is they had no way of knowing that when a decision had to be made. With a roof the potential for collapse would have also been a concern. In any case, I don't think they should decide what kind of facility to build based on a freak event that has happened once in the team's 54 year existence.