During Ace's flashback, Garp will explain how Ace's refusal to run is similar to Roger's.
While my preference would have been to get Ace's whole backstory before he died, this is the one aspect that I really think should have been more firmly established. We've seen a few times Ace's hotheaded nature, but it's this similarity to Roger--the man he tried so hard to reject--that amplifies the tragedy. The only real difference between the two in this regard is that Roger got lucky and Ace didn't.
The whims of fate/luck pop up frequently enough that it adds some extra weight to Ace's death. No matter what happened, he was always destined to die, and no matter how hard he fought against his father's legacy, there was nothing he could do to change it.
