Itachi is an intelligent character that's for sure, but power wise in Naruto verse he barely even makes top 5 Uchiha
Kishimoto made him great in many ways but he would never disturb the verse for his sake alone like we see with Shanks
Itachi only fell behind due to powercreep. However, Sharingan Edo Itachi was dancing around Killer Bee’s swords,saving KVM Naruto’s ass by blinding Nagato’s field of vision, fighting on par with EMS Sasuke against SM Kabuto. Every time he took the stage he made everyone around him look like shit
Sasuke in his delusional revolution speech even admitted Itachi was the “true Hokage.” Itachi has never been anything but wanked. His influence is insane if he was born Ootsuki he would’ve been god status
Shanks still too early to tell. But Itachi set a really high bar with the Hokage wisdom and true Hokage bullshit