Even without a major overhaul in how the offense is run (or coaching change) I think this team would be a winner with a major change in the rotation pattern.
1. Never have Sam and Evans together on the floor.
2. Reverse the Thad/Iguodala substitution. Leave Thad in the entire 1st quarter and send out Iguodala with the 2nd team. Take Miller out earlier so he can start the 2nd quarter.
3. Start Speights over Sam, or at least play Speights 30 min (if possible.) Eliminate Evans.
4. Let Lou get minutes with the 1st team. Give Miller the minutes in the 2nd quarter with the 2nd unit.
Basically, the second unit starting the 2nd quarter should be Miller/Green/Iguodala/Sam and either Rush, Donyell or Theo depending on how big you want to go.
Speights and Lou should get their minutes mixed in with the starters throughout the rest of the game. Do NOT use the current second unit of Lou/Green/Speights/Evans/Thad. It is broken.