Yes, the immigration system is broken and waiting times are far too long but it also suffers because Canada is a country where many people would like to live and the visa officers constantly get lied to meaning that they have to doubt everybody. Yes, some people are poor and still would like to visit Canada and maybe they don't intend on disappearing and staying illegally but how is the visa officer supposed to know which person will do that and which one wont? Same with spousal applications. There are so many fraud marriages it's insane. How is the visa officer supposed to know which one is a fraud marriage and which one isn't without trying to go into it in depth? This of course makes the processing times only longer for everybody.
A few years ago, Mexican citizens were visa exempt to Canada and then people figured out that they could go to Canada and claim refugee status and many did. The result, CIC imposed a visa on Mexicans, see http://www.cic.gc.ca/english/department/media/releases/2009/2009-07-13.asp This is why some countries are visa exempt and others aren't.
A few years ago, Mexican citizens were visa exempt to Canada and then people figured out that they could go to Canada and claim refugee status and many did. The result, CIC imposed a visa on Mexicans, see http://www.cic.gc.ca/english/department/media/releases/2009/2009-07-13.asp This is why some countries are visa exempt and others aren't.