When considering trading players away, remember that their value to a new team matters as much as their value to the Suns. If you trade away only players you don't want, you don't get anything in return.
If anyone wants to give value for Jackson, I say make the move now. He needs to be in a disciplined system where his responsibilities are well defined. With the Suns, it's every man for himself, and that exposes his weaknesses.
The Suns were going to lose last night's game against the Clippers anyway, but the key blow that derailed their desperate comeback was when Jackson tried to force something idiotic from the top of the circle at the start of a critical possession, fed the ball right to the Clippers, and gave up a fast-break layup. It's something like that nearly every game with him, and it comes from being on a team that's asking him to be more than he can be. (Plus the fact that his basketball IQ is so appallingly low.)
Warren is also a candidate to be moved. He's the second oldest player in the rotation behind Crawford and among the most fundamentally sound (which isn't saying much). Looking at his body language, the constant losing seems to wearing on him more than anyone except maybe Booker. It would not surprise me if Warren has already asked for a trade. Booker may also have, but the Suns have to keep him.
Warren is a proven scorer who has expanded his range and is on a good contract. I'd rather keep Warren than Jackson, but Warren has more value and would bring back more in return. And, sadly, I don't see a long-term future for him in Phoenix, because there is only so much he can do and his patience is nearing its limit.
Bridges is undersized and Oubre is limited offensively, but either of them could be a rotation player in a 3-and-D role. Both appear to be better prospects than Jackson. Warren did the one thing people were asking him to do, which was become a good three-point shooter, and his reward has been to be stuck on an even worse team than last season's fiasco. It's a mess all around, but the Suns need to be open-minded and listen to anyone who seems to have a serious interest.