it's interesting to compare this to how moving POPs worked in Imperator on release. It was fully manual, which was great for allowing control in the hands of players, and yes, powers at the time would have had manual movement of populations often. But it was also incredibly annoying to deal with and basically required micromanagement (there was no automated migration). The game also had manual trade route creation like V3, but I can't remember if it could be automated or ever got changed.
Imperator eventually added automated migration and I can see a similar path for Victoria 3 trade, at least as an option, since it has become something which seems to preoccupy a lot of players more than it really should. I know for myself annoyances with trade have caused me to drop the game entirely and enjoy other things instead.