People show a variety of stuff like contact with potential employers/job searches, rental/housing research, letters from family/friends confirming the move, transfer of assets, shipping quotes, research on schools for kids, a detailed plan of support, putting house up for sale in current country. I had letters from family, wrote a plan and showed that I had maintained all of my finances in Canada while I was gone; I probably would have been requested to send more concrete proof but I actually returned to Canada while the app was processing.But I mean even forgetting about the child, how do Canadians living abroad with their spouse generally prove they will go back to Canada? The application process is a year. That's a long time to be able to prove anything, let's say I got a job offer in Canada today, I'd have to act on that right now, leave the spouse here and have her arrive in Canada 6 months later as her TRV is only valid for 6 months at a time.
Is it really this bad for everyone in my position? Is there no known precedence of someone writing a letter expressing intent to do something and that being enough?
It all depends on the VO. Sometimes even all of that isn't enough and that is when they start asking for stuff like cancelling residence permits.
Also, your wife can come to Canada as a visitor and extend her status without issue.