A few years back I had the chance to visit US Bank (Vikings), that stadium is sweeeeeet. Someone from the org showed me a smaller panel of the roof, like you said it's plastic, but two layers w an air pocket in the middle. Apparently they can pump air in to crack ice and snow off. Regardless, it's an impressive building! W that roof and the giant doors that can swing open, it feels like you're outside.
I can go either way on the stadium - part of me never wants to leave Hammer's, part of me would love to stay downtown in a hotel for the weekend and walk to and from the game. I've done a lot of sporting events in cities staying "right there" (including the Bills @ Denver) and it's always been a blast! Something nice about parking your car (or, better still, not even having one) and just walking, eating, drinking and making merry for a whole weekend...
Looking at that location of the stadium I can see events in Conway park, Resurgence and Hartman's will be popping, Canalside would be a whole deal I'm sure, the Casino if that's your thing. IDK, it'd be waaaay different, but pretty fun to think about! Oh yeah, traffic would be a mess, but as mentioned, I'll be in a hotel.
And I still think the tailgate would live on - why would it not? I mean, people with stadiums in cities tailgate and have fun too - we grilled, drank, threw the football, played music, etc. all in the shadow of Heinz Field (no relation). It wasn't same as staying in an RV in OP from Friday - Monday, but what is? Pretty sure the resourceful tailgaters of Buffalo will figure it out...