Hello I was looking back at the chapter where Sasuke frees Tobirama from the black rods and it came to me as to why it wasn't a good idea for him to also free Hashirama. The guy would help the the SA fight the spiral zetsu making quick work of the situation.
Sasuke should have went back then freed Hashirama, then teleport to Naruto. Would have been more logical. That way not as many of the SA will die. Looks like no one cares for the little fodders. They need help too!!