The danger with trading Bagley now would be that Monte would set a very bad precedent for players and agents to just whine and complain and get their wish to be traded.
Much like what happened with Vlade, I don't want the Kings to be viewed as a team where agents use the Kings to get their player that big contract (i.e. George Hill, Dedmon, etc.), whine and then get moved for peanuts to a more desirable destination.
The Kings need to hold firm on getting a solid return on Bagley, either a young player with patential (i.e. Bey or Nesmith or multiple 1st round picks) or include him in a trade to get an all-star level player (i.e. Myles Turner or Tobias Harris) , if they chose to move him. None of this 2nd rounder non-sense.
Otherwise, the Kings would be better off having him stay and prove his worth to the rest of the NBA.