Yeah, the US and Canada could have an EU-style freedom of movement arrangement where Americans and Canadians can live and work in either country without restrictions.Canada and the US would never merge.
The one thing I would love to see the US and Canada some sort of reciprocity when it came to work.
Like because our educational and monetary systems are similar (even though different currencies) you should be able to work in either country without all that gotdamn paperwork. The economies are so intertwined it would be really good, to a degree.
However, the Canadian government would be opposed to that for 2 primary reasons:
1) Many Canadians would flock to live in the US for higher salaries and housing.
2) Most illegal guns in Canada are trafficked through the border because of looser gun laws in the US. Canada wouldn't want more guns being trafficked in (for valid reasons).