You are absolutely correct, processing times varies from the complexity of the profile. Usually, with multiple job and experience letters, huge travel history and personal details cause a delay in processing but apart from those factors one of the major reason to get processed faster or delayed is what Canada needs. They process the applications based on what their economy needs, whether they need engineers, doctors, technicians, sales or just young human capital. We miss this fact a lot many times, that's why they have created job banks and ask you which province you are interested in living. The whole reason to bring in immigrants is to run the economy smoothly.