I am going to respond in turn, and in context. Please bear with me...
I also don't have issues with them taking time to do security checks, but yes, this problem with files being stagnant for some applicants is IMO one of the biggest problems which I think they should tackle to make it more fair for all applicants (as it is stated that apps are processed in the order they are received, but not the case if it sits there in a pile and not even being activated and in progress).
For a very long time (many years) they have had this. It's known as an AOR. AOR means they have: opened the package, and determined that it is complete enough to begin processing. AOR is 'Acknowledgement of Receipt'. Inlands get one, and outlands get two. The case will end up sitting there, and will come up for action items while it waits in queue. These will be processed as time moves forward. Don't take my word for it, order your GCMS notes and see for yourself here:
https://www.canada.ca/en/immigration-refugees-citizenship/corporate/transparency/access-information-privacy/requests-information-act.html . You will see, from the time that the file is received, there are activities going on that you are unaware of. It's very, very clear.
I really think that there should be some standards across the board with all VO's to be able to activate files in a more timely fashion as there seems to be a discrepancy in how long it takes to reach certain stages. For example when an app is received in Mississauga, if they just let applicants know that the app is received and opened, I think it will alleviate a lot of stress and unnecessary calls to IRCC call centre. If the applicants are given a time frame in which their app will get to the sponsor approval stage, that would help too. Of course if there is a spike in number of applicants any one time, it will take longer, however, I still think that more transparency here would take a load off of the call centre.
RE: CPC-M notifying files have been received and accepted ('Opened') see my previous comment above. If you did not get this, you need to work out with the call centre why not.
To your point about VO's and standards. There is standards. Allow me to link you to them:
https://www.canada.ca/en/immigration-refugees-citizenship/corporate/publications-manuals/operational-bulletins-manuals.html .
If you are describing VO's processing in a uniform fashion, that is absolutely impossible. Every case submitted is unique from any other. Therefore, it is 110%
NOT POSSIBLE. Unless you are living someone else's life, exactly.
Regarding time frames, allow me to link you:
http://www.cic.gc.ca/english/information/times/
My real beef was that whilst our file was being transferred to the VO it took 7 bleeping weeks (some cases I saw took even longer), whereas I saw many people whose apps were opened in 3 weeks or less (including those in my own VO). This is something that needs to be standardised. Tell applicants that apps will be transferred in 3-5 weeks. Of course it will take longer if there is a spike in # of applicants etc. However, a whole month sitting there without any movement is crazy and they weren't even processing it. Our VO processes apps in batches. This is garbage. When you are next in queue, assign it to the next available officer. If they end up being too busy, they need to give it to someone else and not just chucked into the "I will get to it 2 months later pile".
See my comment above.
This is my 5 cents I'm throwing in. For us, there is no end in sight in our processing as we have been waiting in queue for an interview for almost 2 months now and still no date and in 20 days, it will be 12 months since they received our app. BTW, none of this has been updated in our GCKey account nor eCAS, whereas others from my VO received an email to say they were in queue several months before their interview date and we didn't get anything.
With respect to VO's and interviews: Paris VO may have way more interviews than, say Kiev. Or vice-versa. How would you propose equalling out the amount of work in the queue? This is why files slow down.
I am terribly sorry to hear you've been queued for an interview. But this lends itself to my point above. Did you supply the proofs required to satisfy the officers that you are a member of the class, and therefore should be approved? If not, then there is no means to standardise, because others did complete this task successfully. I hope this interview, when it happens, turns out well for you! Best of luck here!