I think Iggy holds up very well statistically. He doesn't score all that much but he's the best playmaker of the bunch after Pierce and you could easily argue he's better at it becuase he doesn't turn it over as much. He also scores as efficiently as Pierce because he takes so few shots and a third of them are 3s (which he's making this year at a career best)
I also rate Iggy as the second best defensive SF of the bunch, mostly because he's the best defensive player on the 76ers who are the best defensive team in the league still.
As for Gallo I think he belongs because he's been a much superior offensive player to the rest, scoring 17 points on 12 shots while getting to the line almost 6 times a game is impressive. This is even with his swoon this year shooting the 3 ball.
Batum has impressed me with his production in limited minutes, I really do think if Portland didn't have Wallace sucking up so many minutes he'd show that he belongs in the top 10 of SFs in the league.