The field will be fine. Assuming that this "hardness" thing is resolved, which I'm sure it will be since they have heaters to address it.
The question, again, is how the fans get to the game, park, etc.
It'll be interesting to see how many make it. Someone suggested shuttles from other areas which seems to be a great idea.
Can't imagine that there will be many Steeler fans there that don't live in WNY already though, which is obviously a good thing.