I have the same status . Since have used a rep, I quizzed them about this. Here is what they had to say.
"We just attended a professional seminar on immigration and we received the latest updates. Many quotas are reached for the year and they will not be issuing more visas in those categories."
These are unofficial quotas however country quotas have got over for the larger contribution countries like China and India. Hence the possibility that they will not start security till Jan 19(when the new quotas come online) is large.
Possibly- and yeah ethnic and cultural diversity is important to the Canadian government. But I think there might be other, more pressing factors,
such as labor market needs!
Labor market needs put certain professions more in demand than others. Express entry is after all an economic immigration program! :O and it was instituted to strengthen Canada's workforce.
So, for example, if an LMIA shows that Canada needs more software engineers in the current economy, then software professionals might be likely to be processed quicker than others. My two cents
There might also be quotas based on profession or qualifications- just based on the number of jobs that are projected in various fields. Again, these professional quotas may only exist for economic immigration programs like express entry. So that's my four cents now.