I certainly don't think Walker is going to be traded this season and I wouldn't trade him, but if he was to be traded, I think the team would need a defensive oriented PG and a young big man coming back. Some shooting wouldn't hurt either. Not stars, but that is what the team should be looking at.
So this is a trade I think might work for both teams
Boston - Bledsoe, Hayes, Redick
New Orleans - Walker, G. Williams, Ojeleye, 21 1st
I think that seems like a good trade for both teams.
Boston gets a lesser player at PG, but some potential shooting in Redick, and a potential long term starting center in Hayes. Unless Redick goes back to prior years, that team probably has a slightly lower ceiling this year, but if Hayes pains out it could pay big dividends down the line and that to me is more critical (there is also more salary wiggle room going forward in that scenario better allowing use of the TPE). So starters Bledsoe, Brown, Tatum, Theis, Thompson with Smart, Redick, R. Williams, Hayes being the main rotation and Pritchard, Teague, Nesmith, and Langford getting regularish minutes throughout the season.
As for New Orleans, I think it could use someone like Walker to provide the leadership at point, Grant is a decent fit next to Zion, and Ojeleye is quality depth. They also pick up another late 1st to use in a trade. They can then move Lonzo in a separate trade and still feel good about their PG spot with Walker for the short term and Lewis for the long term. And even if they don't move Lonzo, Walker is a much better and consistent shooter than Bledsoe so he can play off the ball a lot better, which should help their starting lineup a lot more.