This deal doesn't make sense.
Sheed's conrtact is expiring so essentially we get Prince, Afflalo, and cap relief for Amare and Barbs. As other posters have pointed out, Detroit doesn't have a use for Barbs with Iverson, Stuckey, and Rip. Afflalo is just fodder.
It does it your trying to make a run this year. Also, Barbs has a great contract..your not getting that much cap relief so I am sure that's not a factor. They are trying to make the numbers work and I am sure the Suns would insist on a guard in return.
However, this trade would still be a huge gamble IMO. Here is how I see it:
PG/SG
Basically trading Affalo for Barbosa. Barbs is our backup PG/SG. Affalo is just a throw in. Who is going to back up the point? Dragic????? Oh god no. Not to mention you just removed 20 points off our bench in Barbosa.
This part of the deal makes us weaker at guard and thins our bench scoring considerably.
SG/SF
If you do this trade it's to add a younger starter to your SF position. Because the combo of Hill/Barnes has been really good defensively this year so your not getting an upgrade on the defensive end IMO. Just getting younger. Then again, Prince averages almost 8 RPG. The thinking might be here that even though Rasheed underachieves on the boards you make up for it with Prince in your lineup.
This probably also means Barnes would slide over to SG at times (which he is already doing this season at times). This part adds depth to your bench but I think you still have not replaced Barbs scoring by moving Hill to the bench. Plus Hill has not played well off the bench.
PF/C
Sheed is better then Amare IMO on the defensive end , worse on the boards and worse on offense. So, if you make this trade, your doing it for mainly defense. Sheed is an underachiever on the boards as well for a guy his size. Although as stated above Prince might make up for some of that if you insert him into the starting lineup.
This would be an upgrade defensively but you lose alot of points at the PF position. Which means this team then would rely more on the PG/SG/SF positions to score.
Conclusion
This is a huge gamble but if this team wants to take another run at it this year......it might be the only viable option. I don't see this as being a "future" trade because your only getting Prince long term. Sheeds contract will be up and Affalo???
This adds defense to your starting lineup and adds some depth and youth at the SF position. I think the trade off is this team is worse off in the backup PG position and worse off from a bench scoring perspective. From a rebounding perspective it might be a push maybe slightly better because of Prince. It's a gamble.