The problem with applying while abroad has been discussed at length and often in this forum.
As others have observed, there is no reported experience (let alone credible report) of it ever having worked, going back to before there was any intent to reside requirement. Just leaving Canada to live abroad while an application is pending can be problematic, let alone attempting to apply while living abroad. For many reasons which, again, have been discussed in the forum at length and often.
And here again; for example:
In my 17 yrs so far in Canada, I've never heard or read about anyone having done the application and received citizenship from abroad.
So it seems pretty difficult to find someone on a forum with such experience.
Go ahead and try it, let us know how it goes......
And I tend to agree with this as well:
Deep down they know it won't work, but they still want to find at least one example so they can tell themselves maybe they will get lucky too
There are times when some participants in this forum request, or even demand, proof that the process will not work a certain way. And more than a few will insist that absent such proof, it is reasonable to assert that things can work that way. Like applying for citizenship while living abroad.
You have quibbled with what I believe to be obviously true, that
applicants who do not appear to deserve citizenship are at a much higher risk not only for elevated scrutiny but a more skeptical assessment.
Most of us who participate here to share what we have learned and know and understand about the system and the process are not into engaging in arguments about these things. At any given time, the number of non-members accessing the forum, presumably in search of information, out-number the members online by three or five to one. So many of us here are trying to respond to queries as best we can, recognizing that for every question asked there are probably dozens more interested in learning the answer or more about similar questions.
Of course anything any one of us posts is
For-What-It's-Worth, and no one should rely on what any of us posts without approaching it cautiously, critically, and considered in context with the information and instructions provided by IRCC, among other authoritative and official sources.
All that said, I anticipate that there have been some who have applied for citizenship while they are living abroad and succeeded. There are probably three groups of such applicants; yes, this part of my observations is based largely on extrapolation and some speculation:
-- applicants assisted by consultants
-- applicants who make misrepresentations, particularly as to address history and current address
-- applicants in particular, probably fairly rare situations, who on the face of things well appear to
deserve citizenship
The first two groups probably overlap considerably, and probably some of the third group also have used a consultant. I anticipate that among the successful cases, the number who succeeded by fudging (misrepresenting) is the far larger group.
But as others have pointed out, the absence of any reported success doing this tends to weigh heavily for the proposition that, at the least, this is not a viable option.
Anyone who is seriously considering trying it would be wise to at least consult with
a reputable, experienced immigration and citizenship lawyer, a good one. If it is possible, they will have a far better idea about if and when it should work. In any event, anyone who does attempt to do this should be sure to truthfully provide every detail of information, including, in particular, the disclosure of their actual residential address history based on where they have actually lived each month (not using an address they can say was their residential address). Such applicants can anticipate a high risk that their applications will be very carefully if not critically screened.
All that said, it is possible that this government will be more liberal than Canada has been in the past, when even the approach for a Liberal government tended to approach applicants with elevated scrutiny and skepticism if they were living abroad while the application was in process, let alone if they applied while living abroad. (It was under a Liberal government when, in 2005, CIC adopted indications of having returned to Canada to attend the test, or to attend the oath, as a reason to question the applicant's residency.)
Recognizing why the impending implementation of the 3/5 rule has increased interest in this:
I realize that there is increased interest in this, far more so than there was when the 3/4 residency rule was in effect (before there was an intent to reside requirement), because the change to a far more liberal presence-requirement will suddenly make many PRs eligible for citizenship who have not been eligible and who have, in the meantime, either already moved abroad (temporarily or otherwise) or already had plans to do so in the near future. Many of the latter are not eligible now and will not be until the 3/5 rule takes effect. By then they will be abroad. So obviously they have some interest in whether it will be possible.
Additionally it may be worth considering that persons who are abroad for clearly temporary reasons may have better odds of successfully doing this. In the past, CIC and IRCC have tended to approach some PRs and citizenship applicants more liberally, perhaps even overtly more favourably, when it was apparent the individual was abroad for an obviously temporary purpose, such as attending an advanced degree program or pursuant to a specific assignment abroad by a readily recognized Canadian employer (not self or family or friend owned businesses). This could possibly be filed under the category of who appears to deserve citizenship.
Note: I realize you quibble or otherwise decline to accept the way in which I use the word "deserves." I think the way I use it should be readily understood by and makes sense for the vast majority who are interested in these discussions. But, as a reminder, the way I use it is not about meeting the formal requirements for a grant of citizenship, but about the impression a real-life decision-maker is likely to have, and be influenced by, when examining and assessing the facts in an individual's application. 
