If you have been a resident in Canada, even before becoming PR, shouldn't that still count for something, as far as assimilating and absorbing Canadian values are concerned? I don't see how residency experience as a non-PR would in any way cheapen the value of Canadian citizenship (provided, of course, you're an upstanding resident of Canada)? But then again, the US (and most of other countries) does not count the time you spent before you became a PR as well, so maybe the government is just trying to make the rules more aligned with those of the other countries?