Sasuke showing affection is a new addition to his character arc, but it's entirely subjective to say it's good or bad because it entirely depends on whether or not the person reading it likes it or not. Considering the fact that Kishimoto decided to wait until the main story was pretty much over and the last part of the gaiden to depict Sasuke like that, it rightfully comes across as him trying to conveniently tidy everything up so everyone could live happily ever after, no matter how forced and uncharacteristic it may be. It would've felt a lot less forced if he didn't depicted Sasuke as being his old douchebag self when he Sarada finally found him.