User blog comment:Pandawarrior/Why Sabo being alive could be good for One Piece/@comment-3213092-20121001142609

Oda tends to kill people only in flashbacks (Sabo was a flashback), Ace and Luffy took that death pretty bad, especially Ace.

Sabo, if he was alive at that point, didn't show up for Ace's excecution, he had no excuse to miss that(look at Luffy how much he cared to save Ace) and it would be really horrible to just show up in the New World saying 'Hey Luffy, you missed me?'.

Sabo was an example for the two brothers(especially Ace) to have something to live for, and that's one of the reasons Ace continued to live. If Oda wanted to keep Sabo alive he should've clear this out way earlier and with less drama.

I, personally, don't care if he is alive, I won't be mad or anything, but it would be wrong for all One Piece and its story.

Now Sabo being a Marine, I think that's why Coby exists, and Garp filled that gap that he wanted to make his grandparents Marine soldiers..