From my home country it is one certificate with finger prints which clears you from everything. Is Canada different? They did not ask me for anything from Canada.
I suppose your PCC clearance would only prove that you currently are not charged or convicted of any crimes, but security screening goes beyond that, with CSIS and international intelligence agencies exchanging information on whether you are a person of interest (for example, John Smith may have a clean criminal record, but maybe the intelligence of his country has been investigating John behind scenes for potential link to terrorism).
It's unfortunate that processing something as simple as straight forward citizenship applications from upstanding residents has come to an all out affairs between international intelligence agencies, and people like us have to suffer the consequences and endure the delays.