Also seems very likely the British Empire would not have expanded as much as it did into India, Africa and other parts of the world. North America would have taken up a lot more of its energy, seems like.
Settlement would have probably occurred more rapidly. The internal US tensions would probably have been damped, to a considerable extent. Had the US been part of a much larger entity, southern slaveowners would have had a lot less relative power. A lot less likelihood of a major civil war about slavery, IMO.
Interesting stuff to speculate about. Most likely outcome would be a united North America, a much larger and more powerful Canada, if you will.
There are much worse fates for a nation.
Perhaps, but remember that this expansion had nothing to do with wanting territory. The Brits were the biggest trading nation and were making large sums of money from buying up spices and tea in Asia, bringing them West by ship, and selling them in Europe. They needed ports on the route out and back to take on water, food, and other provisions. Hence their footholds on the shores of India and Ceyon/Sri-Lanka, and Africa (e.g. Capetown). Protecting those enclaves ended up requiring more territory around them.