Sage mode had nothing to do with Naruto getting stabbed. SM detects ill intent, at that moment Sasuke didn't have any towards Naruto so he still wouldn't be able to dodge.
Albeit it is Naruto's fault for underestimating the enemy but he seriously was rusty. As for Sasuke, people say he should have brought out Susanoo, but..
1. That giant motha fuka would've taken an hour to bring out especially considering he probably hasn't used it in like 15 years.
2. His kids' life was on the line. What parent would half heartedly try and protect their kid? Some may say even if he failed to bring susanoo he could have still blocked them; but at what risk? One of the knives could have gotten past him and stabbed Sarada.
Albeit it is Naruto's fault for underestimating the enemy but he seriously was rusty. As for Sasuke, people say he should have brought out Susanoo, but..
1. That giant motha fuka would've taken an hour to bring out especially considering he probably hasn't used it in like 15 years.
2. His kids' life was on the line. What parent would half heartedly try and protect their kid? Some may say even if he failed to bring susanoo he could have still blocked them; but at what risk? One of the knives could have gotten past him and stabbed Sarada.