This seems like the best way to go. I'd make it from the day after the trade deadline. What's interesting is, it impacts those bottom teams because they will be more reluctant to just sell off the farm to tank. They will have to measure winning versus trading away players that can bring them a return for the future.
The only issue is it doesnt address the point of the draft, to help out the worst teams. In this model the worst team doesnt get the best pick (or best odds).
But you look at this year where Edmonton (who is mind-numbing in how they are in last place after drafting first for what seems like a decade) and Toronto who clearly went into tank mode, versus a team like the Jets who are actually playing decent and trying to win but could still use help in the draft and should be rewarded for not trying to lose any year of their existence (in Winnipeg).