-2012 First Round pick (top 10 protected)
Why for Phoenix:
Bargnani would be an improvement over anything they have at PF (Frye, Warrick) and he could partner well with Gortat. Gortat could cover some of Bargnani's weaknesses on defense, and the two would create a unique look on offense. Bargnani could also play sparing minutes at Center to give Gortat a rest. Gortat and Bargnani could run very unique Pic N' Rolls and Pic N' Pops.
Why for Toronto:
Trading Bargnani clears our logjam at the PF spot, giving Ed Davis more minutes to develop. We also keep Amir in order to retain our frontcourt depth. Adding Lopez gives us a capable, young center who has burned some bridges and been replaced (Gortat) in Phoenix. Although Lopez is not a big defensive upgrade at center that we need, he is a temporary filler.
Lopez and Alabi could hopefully hold down Center until Valanciunas comes over next year. Lopez is also an restricted free agent in 2012 which means that he would be under team control for a few more years if we wanted to keep him.
Pietrus gives us a defensive SF to play behind James Johnson at least until Kleiza is healthy. He is also an expiring contract so we are not tied into long term money.
But we also hopefully would gain a mid-first round pick which gives us an opportunity to add more young talent.
-2012 First Round pick (top 6 protected)
Switching Pietrus for Childress would lower the protection on the First Round Pick due to his bloated contract. This would help Phoenix get out from under a horrible contract. In theory, we could also maybe use the amnesty to then get rid of Childress.
My worry is that the Phoenix would have the view that they were giving up too much value in Option #1 (young center, expiring contract, first round pick) and are more likely to go for Option #2.
Neither of these trades greatly improve us for the upcoming year (if there is one), but they do give us a variety of options.