How about using the #28 instead?
I don't see anyone buying 28 for 10 million dollars, do you?
As has been pointed put a million times, the Soxers are paying Javale McGee $12 million this season, after having also taken on 1/3 of his $11.5 million salary last season, for a top 18 protected pick from OKC (so likely will be in the 20s if it conveys, or wil never convey, due to the strength of the West.). Is that more valuable than 28? Yes, but marginally so, and it was for 20% more future cap room, and 50% more total dollars. So I'd say 28 is closer to the cost than 16 is.
But also, there's little point in trading Wallace until a better use of that money comes along. I'd rather pay slightly more to urgently move him than pay to move him only to have $10 million unused cap space.
I was not aware that Philly paid that much to get that pick. Thanks for providing the detail. It seems crazy that they took on that kind of salary. Obviously they have no intention of signing FAs this season and pushing up to the cap (so a $12M cap hit is no big) but I wonder if they were playing games with the salary minimum?
In terms of Wallace, I am still not sure it makes sense to "sell" even the 28th pick (or the 33rd as some have postulated that it has more value than the 28th). Wallace on the roster/cap for a year does not hurt us all that much I don't think but as others have said, it would only be done to clear space for a specific signing making the deal:
Draft Pick X + Wallace for FA We Want
That could be a good deal depending on exactly who "FA We Want" is. I don't think you do it just on the hope that some good FA will come or to otherwise just save money.