Officers at CIO have to ensure compliance to the below manual while processing the application. The section 8.1, Completeness check upon receipt, of this manual is under discussion here.
http://www.cic.gc.ca/english/resources/manuals/op/op06c-eng.pdf
On work experience the applicable clause goes like this,
evidence that the principal applicant has accumulated at least one year of continuous full-time paid work experience, or the equivalent in continuous paid part-time work experience, in the NOC 2011 0, A or B occupation identified in their application for permanent residence as their primary occupation. This work experience must have been obtained within the 10 years preceding the date of their application, and the applicant must have:
performed the actions described in the lead statement for the occupation as set out in the occupational description of the NOC 2011; and
performed a substantial number of the main duties, including all of the essential duties, of the occupation as set out in the occupational description of the NOC 2011.
It is thus my opinion that for any application to be considered complete a CLEAR description of job duties is a mandatory requirement. I think the applicant, under discussion here, should definitely send reference letters together with a cover note. In the absence of an explanation the application, under discussion, is not complete. There is a low probability of getting through, though I pray I'm wrong.
I would also suggest to fellows who have not submitted reference letters and got PER should try and arrange these as they MAY BE required by the visa office, when they assess the application against selection criterion, at a later stage. It definitely varies from case to case depending on what alternatives have been submitted.