Some interesting stuff here - I hope you don't mind if I add my two cents.
1. Interconference games are pretty unimportant. As a season ticketholder who sells the majority of the games - No one is interested in the Western Conference teams. They don't all come in every year anyway. In fact, how many people like the Interleague games in MLB? Nice for the first year or two, now they're unimportant and the league would be better off without them. You don't hear about people in American League cities crying about not seeing Bonds or Sosa. No big deal.
2. If they brought back the 4 divisions, and top 4 teams in each division makes it, it would absolutely bring the intensity up in the regular season. No doubt about it.
Back in the day, you'd play your rival a ton during the year and the hatred would build, and by the time the playoffs rolled around, these teams were all over each other. That's the way it needs to be again.
But before you go back, you do need to think of this - back then, a team like Hartford or Quebec would always get into the playoff in the Smythe while a better team in the Patrick was left out. Is the league better off with the top 16 teams in the league in the playoffs, or the top 4 in each division, allowing that teams with better records could be shut out?
All interesting stuff. But the idea is still correct - more games between natural divisional rivals is what the NHL needs to get back to.