I bet my developers in Novosibirsk, Siberia are looking forward to this. It seems like this issue is cared about mostly by people privileged with Mediterranean climates.
This means altering of global and local weather patterns with unpredictable consequences. Some places will get much colder, some will get much hotter. Some places will dry out. Some places will see more tornadoes and flooding.
And some will get both hotter and more humid causing them to be absolutely uninhabitable, because of combination of 100% humidity and over 35 degrees C is basically lethal.
So if you think this is just a "thing", and "what's the fuss, you are going to have more sunshine", you obviously don't understand what the problem is.
I should have specified you to ask someone who actually knows something about building on permafrost, sorry for the omission.
I do agree with you that Canada and Russia are likely to suffer the fewest negative effects. But I wouldn't say it would be a net positive for them either. It's not impossible, but there are a lot of unknowns at this point and a lot of potential feedback loops that could be devastating, like mass extinction level devastating.
This goes far beyond how comfortable the weather is when you step outside.
It is probably the case that there will be some people who "win" a bit as the planet warms, but on the whole I'm not sure anyone will be entirely better off for it in the long run.
Michigan looks pretty good but moving people and infrastructure will be unlikely. Cities will likely adapt and build it into their cost. Miami for example will be underwater but levies and sea walls can be constructed. I don't imagine Miami moving to upstate Michigan.