Why did sasuke...?

[NineSNS]

Oro went by choice - nobody told him to go. Since he decided to follow Sasuke to the battlefield, finding the kages and healing them was a way to add more reinforcements.

 

[Uchiha Samater]

Why did Sasuke send oro to revive the gokage if he wanted them dead?

Oro more than likely went on his own, or at least not under sasuke's order

 

[Honord Sage]

Had Sasuke move sooner against the Kages He would had had the hole Alliance and Naruto move against Him including Madara who would have seen Sasuke plan as a hinderance to His own.

 

[narutoblitz]

A few possible reasons:

1) He doesn't really intend to kill them (I find this unlikely)
2) Oro acted alone, since he's fairly random (more likely)
3) They needed help to take down Madara and Obito (now he wants them dead)

 

[Zeolance]

Sasuke didn't send him. Orochimaru went on his own.. of course, he might have said something about it... but oro went on his own.

 

[Draxus]

Oro decided on his own that Gokage would be useful to Sasuke in the upcoming battle. At that point in the story Sasuke probably didn't want to, or didn't think he had the power to, kill all the kage.