Its not a plot device. If you're going to look at it that way then most of the battle tactics in Naruto could simply be labeled as plot devices, Naruto is just an idiot.

Sasuke has exceptional speed which is the only reason he tried that because not only did he have the sharingan so he could clearly see all of Tobi actions he had enough speed to counter him in the event that he did do something. That is the same logic he used when he was fighting Gaara during the chuunin exam.

Yes, I know Tsunade issued the order but that is not their mission. Secondly it was what 8 on 1 if they have a chance to kill Tobi it would only be because they are all together. Hinata has the Byakugan, Kakashi has the sharingan, Kiba can sense how strong an opponent is by smelling their chakra, and there is still Yamato, Shino and others so there was no need for Naruto to do what he did. They have enough abilities to analyze the situation and possibly neutralize Tobi, all he had to do was wait and let them assess the situation and come up with a plan of attack.

Naruto is an idiot.