The term used on this site is any nation that started out as a colony of a 15th-19th century European empire
What he said.
Overall I like them being in the game - interesting mechanics, add colour, scratch an itch for people that want certain countries represented.
But the implementation is not great, really. If you start in the ancient era they are anachronistic. But worse, one of the things that’s cool about colonials countries is that they were colonial - they were originally settled by another country, far from the shores of that country, and then rapidly made a place for themselves in world as an independent nation.
Civ catches none of that - not the voyage to distant and strange lands, not the struggle to adapt to a new environment and exploit it, not the break from the old country, or the sudden and rapid emergence of a new global power.
The specifics are different for each colonial nation in the game, but the overall arcs are fairly consistent.
I’m not sure there’s much Civ can do about it, really. If you’re going to have, say, Australia in the game, then they need to start in the ancient era with everyone else because that’s how the game mechanics work.
But perhaps Civ could try to fill the gap a little. First, maybe the game needs some sort of colonial mechanic, where you create colonies on other continents and these colonies have a degree of independence or are at least are just visually different. And second, maybe the game needs some sort of optional staggered start mechanic, or just a colonial scenario, so I could start as a colonial Civ on a map that has existing established “old world” powers.
I think when you have 40+ civs in the game, having 4 or 5 colonial civs is fine. America has been a staple through the series, and I've enjoyed having Brasil around the last couple times.
I do think they went a little stereotypical overboard with Canada, although they did that too with Scotland previously. Although at least they did something kind of unique with Canada, so we'll have to see how it plays out. I do wish they went a little more into history for the civ - honestly, personally, I kind of hoped mostly that our UB would be the grand railway hotel, and was hoping the UU would be a fully non-combat unit. Or that they did something unique with aerodromes, for example, and gave them like a free trade route if built on tundra. Maybe the civ will play really fun with the new systems, but it definitely seems a little over the top, that I agree with some of the above that it would have been nice to focus on some historical traits, and not just "mounties and hockey".
Railway Hotel is a good idea.
Pity they didn’t go a non-Military UU. That would have been unique and very striking.