The problem with the NBA and NHL isn't the length of the regular season its the length of the playoffs. WAAAAAAY too many teams and the series are too long.
The NBA made an enormous mistake extending the first round to seven games. It was completely pointless and drastically cuts down the chances of an upset happening in the first round. As for the NHL, I'm not a big NHL fan but a #8 seed taking down a #1 seed apparently isn't very rare which completely renders the regular season meaningless. What's the point of working your arse off to get the best record when it really gives you no significant advantage? Also, it seems like there's a mediocre regular season team that has a goalie get hot at the right time and goes deep in the playoffs every year. The NHL regular season just doesn't seem that important. All you have to do is make the playoffs and get hot at the right time and anything can happen.