And would any fans really care or would it make any difference to the battle if all those fodder ninjas died? Now Sakura is just back to healing again, regardless of if it's an "impressive technique."
Sasuke had terrible motivation to become a traitor and and terrible motivation to come back into the fold. He's not even sympathetic because he's acted like an asshole the whole show. And his friendship with Naruto isn't even properly built up to feel bad about it falling apart.