Yeah, I agree, and to be honest that kind of bugs me. I know h'es old, sick, and has been stabbed straight through the stomach, but c'mon we've gone through most of the series hearing how Whitebeard is the closest thing to the pirate king.
I will in no way compare this manga, or Oda, to Naruto (and I am aware even mentioning it is blasphemous
), but it's just reminding me of the disappointment I had for Itachi... Hyped all series, only to be seen in one fight, at a disadvantage and sick, but somewhat excused because he was planning to throw his life away. Now unlike Naruto Oda, rarely disappoints, so I am still hoping WB does -something- aside from sinking an island.
At this point I don't see Akainu dying. He has set himself as a good antagonist and I think he'll help tap into Luffy's dark side for revenge as motivation. I strongly doubt it would happen, but it'd be interesting to see Sengoku die and Akainu become Fleet Admiral. He is definitely the most precise in his "justice".