This is the weirdest/worst idea I have ever heard.
Most people who love the CFL love it because the different rules make the game much more fast-paced and unpredictable.
The two biggest things for me are the 20 second play clock and the single point. There's only two ways to score in the NFL (other than extremely rare safety), which makes it quite repetitive. I love that you can score a point off a punt, a kickoff, or a missed field goal in the CFL. The extra point being moved back in the NFL has helped decrease the predictability of the scorelines, but it's still typically 24-17, 14-10, 28-20, etc in the majority of games. I hate that aspect of it. Give me some 33-29, 22-18, 26-25, etc, different scores every week.
The 40 second play clock is the other thing I can't stand. It's not a big deal in the first three quarters, but if you're down two scores in an NFL game with 5 minutes left and the leading team has the ball, the game is basically over. The ability for a team to kill three, four, even five minutes of clock by picking up a single first down just plain sucks. Victory formation with 2 minutes left is awful. In the CFL you can reasonably give yourself three possessions inside the last five minutes if your defense holds.
If either league were to adopt a rule from the other one, I'd like to see the NFL use CFL clock rules in the last 5 or 10 minutes of the 4th quarter. And I'd like to see the CFL adopt the fair catch rule on punts. The returner hovering over the ball on the turf waiting for somebody to breach the 5-yard zone is lame, as is the high-speed guesswork involved in the officiating of those plays (though oddly enough, CFL refs usually manage to get these ones right).