My Kage Tier List:
Top Tier - Pein, orochimaru, Kisame, deidara, Itachi
Mid Tier - Kakuzu, Hidan, Tobi, Sasori
Low Tier - Konan and Zetsu
Top tier - Powerhouses. Great on the battlefield. Can destroy armies and support troops. Also great 1v1.
Mid Tier - Good on the battlefield but not so good 1v1 or vice versa (Good 1v1 but not good on the battlefield)
Low Tier - Good enough on the battlefield and 1v1 compared to other fodder ninjas (Around Jounin/Low kage tier)
Pein is top tier. I dont need to explain why.
Orochimaru is top tier due to big summons and jutsu versatility. Strong in 1v1 too.
Itachi is top tier because of Susanoo and Amaterasu. Itach is more 1v1 than big scale battle but he is strong in both nonetheless.
Kisame is also top tier due to huge chakra pool + he can summon floods, lakes, etc. Kisame is strong 1v1 too.
Deidara is hi-kage level. He can destroy a whole village and wipe out armies with C4. There is no dispute. 1v1 he is good if he can set up his traps and jutsu. 20 m or less, his head gets blitz off.
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Kakuzu is mid tier. Good elementals for the battlefield + black threads to utility and support (Stitch and capture). I don't see his elementals doing big damage like the guys up top so he is at Mid Tier. Strong 1v1 as well.
Hidan is Mid tier because he has a very strong support blood curse jutsu. Very good on the battlefield to assassinate top tier officers/generals with support from other Ninja. Hidan is also good at close quarters cqc.
Tobi is Mid Tier because he is very strong 1v1 but in a big battle, he doesn't have powerhouse jutsus to wipe out armies. Mostly Katon variants though less versatile than Kakuzu.
Sasori is strong mid tier. He is like an Alien Queen from Aliens sending hordes of bugs (Or puppets) against his enemy. He does well in big scale battle. 1v1 battle not so much. Against a guy like kakuzu or 4th Raikage, he'll be utterly destroyed.
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Not bothering with low tier.
Its understood.