Here's a scenario that will, for sure, happen to some people:
Say you get your citizenship according to the new law, and few months later you get a good job offer from the US. You leave for 2 years, and then decide to come back. During your absence, a lot of people gets their citizenship questioned due to leaving Canada immediately after obtaining citizenship (it is going to keep happening, no matter what law the government puts in place).
So, you want come back to Canada, you even found a job and have an offer, but you get in trouble because now you are being treated / regarded as one of "those guys".
The question is: you loose your citizenship, what are you then to Canada? You are not a PR anymore, because you lost that status as soon as you became a citizen.
Are you a visitor, do you need a work visa? Kids are starting school in 2 weeks, job offer is waiting, your spouse is looking for work as well... and then what? You go back to where you came from originaly? Start fighting the system, prooving that in the moment of signing the intent to reside, you weren't looking for that US job?
I became a PR a few months ago and have no intention whatsoever to leave Canada, but it is not hard to see that a lot a honest people will get in serious truble because of those who are abusing the system. And the number of abusers will remain the same, they will just have to adjust their timeline a bit due to the changes in the law.
I understand the increase from 3 to 4 years, I even understand no more pre-pr time (even though it affects me)... but intend to reside is something that can, and I'm affraid will, be used in a bad way.