Worst team gets the best draft? Then what is the point to even try to win games once you're safe?
Well that's a reason it wouldn't work with relegation/promotion as mentioned above.
Could easily work; the play-off team gets first pick, the second place finisher in the championship gets second and so on.
It's just a shit system that's harmful to the competitiveness on sports. I've got two friends from Toronto who both supports the Maple Leafs, once it was decided they weren't going to the play offs, they were actually hoping for them to lose.