When Sasuke was dying against Madara, Tobirama said he could save his body with a technique.
Putting things together, Tobirama was probably thinking of using the Impure World Reanimation technique on Sasuke. This would have given us a reanimated EMS Sasuke.
That raises some questions and ideas.
1) Can a reanimation grow?
Either actual physical growth or growth in power and strength. Would Sasuke have been limited to that power level if he was reanimated? If he would be limited, could he have cheated by eating Senju DNA to awaken a Rinnegan, or trained in some sealing techniques to become a beast host or to absorb superior energies and thus improved his power level?
2) Would he have been stronger?
He would have the classic undead benefits (mutual death strike), essentially making him a Sasuke+Hidan mix who does not need a partner to sew him together. He would have been able to sustain his MS powers much longer (infinitely, actually) and probably use them at a higher level since he could spend more energy on them at any single time (basically, bigger flames and armour). His non-Uchiha powers would also be stronger. He would be able make bigger lightning spears, use Thunder Giraffe more frequently, summon more shadow snakes and copy many techniques that he could afford to use at a good level. So, would he be stronger as a reanimation than he was against Kaguya or Kinshiki or now (lost eye)?
3) Would he have been useful?
The reanimation state restores the body. Would he have been able to copy techniques, since those techniques are probably stored in the physical brain? Could he have taken the Moon Seal from Hagaromo, assuming thay conversation could even have happened? Could he have received Six Paths Energy to evolve Rinne-Sharingan?
4) How would the story have gone?
If EMS Sasuke was a reanimation from that point onwards, how would the story have gone? Would he have been a main character as he has been or would others (Golden Generation) have been made to step up? How do you think things would have been? Who would Sakura have married?
Putting things together, Tobirama was probably thinking of using the Impure World Reanimation technique on Sasuke. This would have given us a reanimated EMS Sasuke.
That raises some questions and ideas.
1) Can a reanimation grow?
Either actual physical growth or growth in power and strength. Would Sasuke have been limited to that power level if he was reanimated? If he would be limited, could he have cheated by eating Senju DNA to awaken a Rinnegan, or trained in some sealing techniques to become a beast host or to absorb superior energies and thus improved his power level?
2) Would he have been stronger?
He would have the classic undead benefits (mutual death strike), essentially making him a Sasuke+Hidan mix who does not need a partner to sew him together. He would have been able to sustain his MS powers much longer (infinitely, actually) and probably use them at a higher level since he could spend more energy on them at any single time (basically, bigger flames and armour). His non-Uchiha powers would also be stronger. He would be able make bigger lightning spears, use Thunder Giraffe more frequently, summon more shadow snakes and copy many techniques that he could afford to use at a good level. So, would he be stronger as a reanimation than he was against Kaguya or Kinshiki or now (lost eye)?
3) Would he have been useful?
The reanimation state restores the body. Would he have been able to copy techniques, since those techniques are probably stored in the physical brain? Could he have taken the Moon Seal from Hagaromo, assuming thay conversation could even have happened? Could he have received Six Paths Energy to evolve Rinne-Sharingan?
4) How would the story have gone?
If EMS Sasuke was a reanimation from that point onwards, how would the story have gone? Would he have been a main character as he has been or would others (Golden Generation) have been made to step up? How do you think things would have been? Who would Sakura have married?