One Piece thread (Spoilers)

A cover page doesn't really have significance to the story. I would think in the middle of drawing the landscape and specifically drawing that stake, that it would be positioned in the heart if the intention was death. Also that's not accurate either, Oda has constantly stripped the significance of moments like that, Pell being the biggest.

Can you name me one time that one piece has completely off'd a character who's intentions weren't entirely clear? Yes she wants to help donflamingo become pirate king, however, who gave the note to chopper? It was most likely was her and for what reason did she want them to escape? Plus majority of villains, I would say 90% aren't killed but reformed. Bellamy/nero were examples to essentially to show how cruel the actual villains are, so they aren't good examples as to oda's writing style, where he milks every death scene for what it's worth.

Now that I think about it almost every villain has been revisited besides don kreig and Kuro

On the contrary - Oda has consistently used his cover arcs as a narrative means to show the reader what previously dispatched characters are up to, and, especially in the case of Crocodile, to set characters up for later re-introduction. Crocodile was set up to be re-introduced as a major character in Impel Down this way; the cover arc illustrated for us his refusal to leave his imprisonment. Also, Hachi's cover arc was used to redeem his character from his villanous role in the Arlong arc, which later paved the way for his re-introduction as a major player in the Shabondi storyline. Oda's chapter covers don't always contain story-relevant material but when they do, they're definitely important. But I guess this would be another debate over opinions, ahaha;

Keep in mind that Oda has his own team of assistants to draw in scenery for him, and has himself said he mostly is responsible for character artwork rather than landscapes. I'm sure he does draw landscapes himself but it's more likely that background elements are assigned to assistants.
Also, we never actually saw physical evidence of Pell's body after that explosion either, whereas we clearly saw that icicle driven through her heart. And again, where that icicle ended up after that doesn't cover up the fact that it was stabbed into her heart first.

I do agree there's definitely reason to revisit her character, though. I was very curious myself as to what her intentions were when it came to letting Chopper go. But until Oda himself lets us know in detail what happened to her, I still feel like she's more likely dead than not. Oda could just as easily reveal what her intentions were in other ways, such as by revealing her affiliation with another party. I happened to feel that her death was meant to emphasize of Caesar+Doflamingo's cruelty just like Bellamy and Nero's were, and it adds a wonderful element of suspense since we won't be able to figure out what she was up to until Oda decides he wants to explain. Also, the only time he really milks death scenes are when the characters in question are protagonists, really...but in hindsight, I can't say it's rather fair to map Oda's writing style to a specific formula, either. To do so would suggest he's predictable, and he's most certainly not. But, like I said, if he does end up somehow explaining her survival, I'll stand corrected. xD