Ro, your argument about no one else does it sounds good until you take it out of the theoretical realm.
NHL - after the division winners, all 5 conference playoff spots are wildcards, meaning they earn spots based on ranking, regardless of division standings.
The same in the NFL.
Now, while neither league crosses conferences, there are a lot more teams, and the gap between who's in and who's not is small - in football, rarely more than a game. I can't remember the last time a team two games worse made the playoffs over another. In hockey, maybe 4-6 points at most, after an 82 game schedule.
This year, it is more than likely that an 8-9 win team will finish 4th in the west, while the third place teams in the East could have as few as 5, possibly even 4 wins, despite playing a far weaker schedule. Other than geography, what precisely has that team done to earn a spot?
The anti-crossover movement was born in the East for obvious reasons - it takes a playoff spot away from a weak eastern sister, and throws a much tougher opponent into the Eastern playoff mix. There's no doubt Montreal would rather wipe up whatever "winner" comes out of the Toronto-Hamilton-Winnipeg mess, but toss in ANY Western team, and that's a whole 'nother matter.
This would not even be a discussion if the relative strength of the divisions were reversed.