Ebor,

With your #1, I think you're missing the point. You wouldn't need to learn new fingering on the fiddle if we played in one key all night, as we'd play tunes in their "proper" keys. Not like we'd play "Drunken Hiccups" in C, because it's an A tune.

And we'd play all manner of tunes in each key.

And just for you, we'd change keys every couple of hours, ok? ;-)