Middleton would be perfect as our starting SF. I'd try and trade Aminu for a 1st and offer the pick with the two 2018 1sts and filler. But I'm afraid Middleton is untouchable, but Tobias Harris was a same level player on the same kind of contract who got traded for a whole lot less.
Milwaukee could go younger and cheaper because Antetokounmpo is only 21 years old. Maybe trading their expensive contracts (Middleton, Monroe) for assets and cap space then using the capspace to buy free agents who fit with Giannis, Parker, and MCW would be the way to go.
The moves would leave us with around $35M in cap. That means we could sign someone like Horford + Role Player(s), which would then bump us to a top 5 NBA team. It'd be an Olshey move nobody saw coming but would make a ton of sense.