The whole reason to trade Thompson is for money/cap management purposes. To me, it would make no sense to involve someone like Wiggins who has an even worse contract (by a lot). You would also consider trading Tristan in a swap for a player that can be on the court with Horford, such as a PF (most likely) or a PG. But we are stacked with wings, the last thing we need is another one. I would by far rather just sign Fournier to what will likely be a lower cost contract than get Wiggins and let Fournier walk. Fournier + Thompson is way better than Wiggins.
Thompson by himself is not going to get us much. I would love to be able to clear Thompson's contract. I don't know all the teams that might have a $10M TPE on hand but that would be the ideal scenario. Send out Tristan and swap second round picks with someone who has a TPE. I don't want to take back salary for Thompson just to take back salary and we probably are not going to get much of player in return so why bother?
Smart and Thompson combined could be good in the sign and trade or regular trade market. That is about $24M or so and could fetch a decent player. But then we go from a team that only needs a good PF to a team that still needs a good PF and now needs a good PG too.
So my trade is Smart and Thompson with Edwards and GWill for Simmons and Paul Reed. Simmons can play both PG and PF albeit not at the same time of course. Both Problems solved, perfect. We just have to teach Simmons to shoot FTs and we are a championship contender.