I understand, but we have to start somewhere.
Washington is in a massive bind. They are projected to be in the luxury this year ($5.8 over) and next year (an estimated $10+ over if you include the necessary minimum contracts). Because of their situation, Mahinmi is considered one of the worst contacts in the NBA. He is set to make around $16 million this year and the next two years. Many think his contract is untradeable. Many have speculated that the Lakers might trade Deng because he also has a bad contract. However, compared to Washington, Deng's contract is not as toxic. Deng might keep LA from getting two full max contract players, but his contract is not leading to the massive luxury and repeater luxury tax area like Mahinmi is doing to Washington.
So if we can find a way to take Mahinmi off Washington's hands AND help them avoid the luxury tax this year, we can ask for a whole lot in return. I think Rubio is a realistic trade piece for them, but they might prefer an expiring like JoeJ or Favors. If we give them an expiring, they more than likely avoid the luxury this year and next then can keep Oubre when he needs to be re-signed in 2019. So the question is, would they trade Oubre? Not sure. Do we want Oubre? Not sure. But if we gave them an expiring for Mahinmi while getting them out of the luxury, that should be worth numerous unprotected first round picks.