You can't compare Akainu to other middle of the road villains, he's made to be the terminator of One Piece. 1 hit is all he needs to put characters in the grave. After sending Ace and essentially Whitebeard to heaven, it took another Yonkou stepping in, and not before he put a hole in Jimbei (incapacitating him until Law saved his life), even a graze from his attack left a permanent scar on Luffy.
Akainu's offense isn't so cute that he'll go around the island knocking people out, crossing paths with him when he's out to kill there's no coming back from that. Trading blows with Akainu is never going to be in your favour.
Oda really did well with his character, his ability is well suited for his role, it makes him arguably the most imposing character in the series. There's no middle ground with him, he's always lethal. Just like a mad dog.
Only BB can be compared to Akainu in terms of moving the plot forward, these two are made to be the focus of each world, the pirate world and the navy side of things.
It's unfair to compare any other villains to Akainu or BB, they're built to succeed and have personal history with the MC.
