I looked at the playoff brackets for the Stanley Cup Playoffs since the 1997-1998 season. The results were quite interesting.
For instance, it’s not the top ranked teams in each conference that have the highest winning % in the first round. Surprisingly, since 1998, the 4th seed in the East has won 89% of the time and 67% of the time in the 2nd round (also the highest). With the 4th seed having such high winning %, that means that the 5th ranked team in the East has only won 11% of their first round matchups. Further, the 5th seed in the East and West, as well as the 8th seed teams in the East have never advanced past the second round.
The seed that has enjoyed the most success in the playoffs is 1st place in the West. They win, on average, 78% of their first round matchups, and have won the Stanley Cup 3 times since 1998.
In the West, no team ranked lower than 3rd has won the Stanley Cup, while teams seeded lower than 4th in the East have never won.
If the playoffs started today, this is where each team would be seeded: