Saskey need hatred to become stronger...he is actually being nerfed when he is peaceful saskey because sharingan get stronger with hate nd sadness...
just with plot alone, saskey staying would be bad for him... he might get one good win like Sakura vs Sasori sana or Shikamaru vs Kakuzu but then he would get solo a lot until a war arc so naruto coon get all of teh cool moments...