The idea that you suck to win indicates a change is warranted. It's not in the spirit of sport. The reason teams intentionally suck is to get a top draft choice.
With relegation, you eliminate the suck to win dynamic. The risk of getting dropped from the top flight would make most every game competitive. For me, that means lots more interesting games throughout the season, and all kinds of new dynamics end of season when teams on the bubble are fighting like crazy to stay up.
Alternatively, you can abandon the draft or rotate draft picks. It wouldn't be as interesting a change as relegation, but would help. Just get away from this model that you benefit from sucking.