Again, I don't want to trade Hayward, but I had this thought today:
Boston receives: Giannis, McDermott
Milwaukee receives: Turner, Warren, pick 2 of Langford, Williams, and Williams, 14, 27, 30, two future Boston 1sts
Indiana receives: Hayward + Lopez, Hill, or Bledsoe (Indiana's choice)
Why for Boston? Because it's hard to get an MVP player and Giannis would be deadly next to the other Boston stars. I recognize another trade would need to be made eventually, but for one year, Boston would be fine.
Why for Bucks? Because this allows you to get younger, to get a variety of future draft assets, and still stay relevant in the playoffs for your fan base.
Why for Indiana? Turner is a frustrating disappointment, but this allows you to reform your team. If you want to be able to stay big, take Lopez. If you want to go smaller, take Hill or Bledsoe. Hayward is a better all-around player than Warren and he is an Indiana boy.