To be more open to more possible matchups for Sakazuki, let's look at the most obvious one besides Luffy.
Oda is using this theme all the time to show that there's history between certain characters.
There are probably much more examples but the point is obvious. Oda does this only when the characters have a history and bad blood between them and Akainu surpassed all of the above by spamming it time and time again.
As much as Akainu disrespected Whitebeard it sounded like he had quite a bit of respect for Dragon and Roger putting their name on the same level as criminals.
Akainu was so hard after Luffy because in his mind someone with Dragon's potential is more dangerous to be allowed to walk away than even Blackbeard.
- Both are 55
- Akainu joined the Navy roughly at the time the Revo army was founded ( if the timeline hasn't confused me)
Looks like there are quite a bit of connections.