It is a great idea because it would keep people from buying teams just for playoffs.
The only issue is that some people would just buy those players sooner in the season before the trade deadline so it wouldn't truly create a new outcome.
It would help teams that would play against those teams who try to buy a championship with being able to see those players play a few games before the playoffs did come.
I like the idea of a trade deadline a week before the end of the season. I would keep the current system with bids still in effect even though they are ineligible for playoffs so not a complete trade deadline. More like a playoff ineligible deadline.