I think he'd get the somewhere between the BAE and taxpayer MLE. He was not as bad as you are making him out to be. Similarly DJJ won't get full MLE after the season he had and he was benched in the playoffs. Its absolutely an exchange of bad goods. They might get a guy at the minimum but they are one of the weaker West teams when it comes to centers. Nurk is also grumbling about a new contract... they need some stability. Not sure they can afford to gamble on a guy like Dedmon or Biyombo at the minimum with Dame wanting to see progress.
I don't think Favs trade value is as low as some might... he's definitely a negative. Had a bad series against the Clips but had some good moments against the Grizz.
I will admit that I'm lower on Favors than most. But to me DJJ is more or less the same as he was when he signed his contract. He's still young, still has potential, and still has the flaws that got him benched. All of the reasons why he got that contract are still more or less there. A year later it does feel like his potential is getting too costly, especially for a team in a bind like POR, but ultimately I don't think the outlook for DJJ is much different than it was a year ago. If we want to try getting a stretch 5 and playing him in lineups with DJJ, I don't know why POR doesn't want to do the same thing.
OTOH, I think Favors stock has dropped considerably further. He looked completely cooked physically and was awful at what was supposed to be his biggest positive (defense). I do agree that POR needs some consistency and reliability from the C position, but Favors is absolutely not that player because of his health and obvious shortcomings that he displayed when he was playing last year.
I don't feel great about penciling in DJJ as a rotation player, but at least he has upside. I also don't feel great about penciling Favors in as a rotation player, but he plays a position that is significantly easier to address with cheaper options and has no upside.