I thought I recalled the TiCats botching 1 this season.
Since the Rugby World Cup last year, I've been paying more attention to that sport, which also has conversions. I was surprised when I realized that they weren't an automatic 2 points after a try (a try, corresponding to our touchdowns is still worth only 5, like it used to be in Canadian and American football).
Rather than getting field position that makes the conversion automatic, like in the North American games, the ball is placed anywhere on the line parallel to the sidelines (touch lines in rugby terminology) through the point where the ball was grounded (or "downed" in our terminology, except that the ball is required to actually touch the ground). If the ball is ground far enough from centre, the kick is harder to make. A rule like that could make the PAT less automatic.
I don't see us moving towards the rugby rule, though (especially since the ball is always snapped from within or on the hash marks in gridiron). So, we could skip the convert altogether and make a touchdown worth an automatic 7 points, but give the teams an option of another offensive play from the 3 yard line which, if successful, would earn 1 more point and if unsuccessful would lose 1 point. This would make things effectively the same as now, but without the time spent on the convert.