Well, you could argue that Akainu was promoted because he managed to win a 1vs1 against another Fleet Admiral candidate - who was even recommended by Sengoku, an old legend. The FA candidate in question managed to have a punching contest with Old freaking Garp and we haven't even seen the skills which turned Punk Hazard to the current state as it is.
Yes and if you conclude it logically the Akainu that fought for 10 days was his peak, therefore why he became a FA and literally what I meant with what we haven‘t seen in his full potential, but to be frank fighting for 10 days could also just be statement that their AP isn‘t high to begin with.
You could argue that one way or the other way, but my point is that is peak Akainu and probably the reportoire of his skillset being unseen.
So MF Akainu is Admiral level, the 10 days fighting vs Aokiji = Akainu‘s level as FA.
That is the Akainu we haven‘t seen. The only logical boost Akainu could, receive (doubting it) would be if he submits himself to Imu.
So my point is Akainu has so to speak ” 2 levels“ and a possible 3rd.
1st Level: MF Admiral Akainu
2nd Level: FA Akainu that fought for 10 days. Maybe a little bit amplified for a possible Haki bloom. So this is the Akainu we‘ll see next when he fights seriously.
3rd level: A possible Akainu that submits to Imu