@shinpfn:
I wondered about this only untill Wapol appeared on those mini-arcs. Since ODA left Wapol run free, I believe that nothing prevents Kuro, Krieg, Arlong or any other to return and do the same cruelties they did before. This I see as a flaw in the work, but then again, if ODA was not like that, we would fear much more the risk of a SH dying. And since ODA does not have the guts to kill a villain (if by SH hands that is), I believe he will not kill a main character (avoiding the need to ressurrect someone DBZ style as well, god forbid that). And at least it seems that Belamy did die, and for a second, it looked like Aokiji would really suceed in killing Robin (wich contributed to sustain the tension). We should bear with this ODAish thing I think. Those that can not, should probably just drop it.
What prevents Kuro from running rapant again is the fact that he wants to quit being a pirate. His plan as Syrup won't work now that Kaya knows, it'll take years to do the same years again, and if he tries any piracy, he'll be doomed to the same life of being constantly chased by the marinies that he hated so much. That pirate ship is a prison for him. Oh yeah, Sham, Bucchi, and Jango are gone, so that crew is weakened too.
As for Kreig, I'd imagine it'd take forever for him to gain his power (armor and crew back) he was left with only a rowboat for his 5000 men and Gin KOed him without that armor. That armor couldn't have been easy to come by, and his crew may not even want to stay with him, now that he's unarmed they can easily run away.
As for Arlong, he's captured by the marines. Just cause the marines couldn't catch him before (and they only tried once it seems), doesn't mean they can't hold him. Just wrap him up Hannibal Lectur style.
Yet, the major pirates in East Blue were wrapped up pretty nicely if ya ask me.