@Sereques:
Shank's death at the hand of Teach is too big of a distraction to be played down as a mere element. The focus should be about One Piece.
You are aware that finding One Piece is going to happen well before the actual end of the series? And that the final battle will have to do with what the characters learn upon finding the treasure, (and thus the history) not to get the treasure? That the great war will probably take a couple years real time after One Piece is found? (And thus Robin will be the first one to complete her dream…)
The series' final goal hasn't been simply to get to One Piece for quite some time. The hints were there since the ancient weapons got mentioned, since we started getting bits of the true history in Skypeia, Rayleigh said it pretty clearly at Shabondy, and Whitebeard's final speech set it in stone as a promise of what is to come.
Oda's had his say about revenge as its own means to an end already... in showing that Ace's pride of wanting to avenge someone as his downfall, and that Hody's revenge against the world was empty and shallow. He wouldn't play retribution straight as its own means to an end.
Luffy went and stomped down Arlong because he made Nami cry. Beat up Bellamy because he hurt the walnut head. Demolished the Franky Family for hurting Usopp. Punched out world noble for shooting Hachi. etc. Always "revenge", always for the sake of his friends... but never a singleminded absolute goal. Luffy has had close friends, brothers, die... and it doesn't sink him into complete despair... he gets over it moves on and gets stronger.
It would be an element to make the FINAL villain more personal, to raise the stakes and complete the message of generations passing on their dreams... but it wouldn't be an all encompassing theme. If you're thinking that you're missing the entire point and the multitude of reasons being named for Shank's death.
(And you know Oda could pull some crazy heartstrings with the symbolism of the hat and the old promise and some well timed flashbacks)
@Cruithne:
Y'know, should we take this to a "Will Mihawk Die?" thread?
No, there was a whole smattering of offshoot "Will X die" threads the other day, that needs to be cracked down on. This thread contains the topic well enough.