Itachi's role was to protect the leaf. Obito was the biggest danger to the Leaf so it was Itachi's job to do something about him. He tried a last ditch effort by rigging Sasuke's eye and it failed. You cannot change the reality of what's been shown in the manga versus your opinion.
Spacte-Time, Izanagi, Wood Release, Barrier Technique and the ever-deadly chakra rod/pipe he used to penetrate Konan from behind. Obito has been able to control Kurama and multiple beasts easily, and even tricked Itachi into believing he was Madara. For a genius, Itachi was sure duped.