I think Turner or Sabonis would be a great fit here but A straight up trade for Brown is a no go for me. We would need more in return than that. Brown still has All-star potential if he works hard I don't think either of those guys do.
To be clear you are saying the guy that averaged 13/4/1.5 with a TS% of 58 who regressed from year 2 to year 3 has all star potential but the guy that averaged 14/9/3 with a TS% of 63 that has significantly improved each season (also in year 3) doesn't have all star potential. And they both played around 25 mpg in a mostly bench role so it wasn't like the minutes inflated the stats. They are also about 5 months different in age.
Also, for the record, Turner is also basically the same age though has the extra year in the league. His TS% was 57 and he led the league in blocks per game at 2.7 and finished in the top 10 in all sorts of defensive metrics. Now I will give you that Turner's per minute production has basically been the same all 4 of his seasons, so he might not be much more than he is, but what he is, is an absolutely elite big man defender, which is still more valuable than a defensive oriented wing.