No. Its a relevant element that will serve the storyline and its narration.
How will Zoro and Franky's statements serve any purpose in the plot, especially as the opportune time has past. At best they can only serve as an afterthought of either a flashback, or reason why they didn't attempt to fulfill their declarations, but either way their plot point will be less than relevant to the current situation, and even then that'd only raise questions on why these matters weren't significant to the characters during the readiment of the war.
No. That's not how it works mate. Again, you are confusing plot point and plot line.
Plot points can be left behind, never to be relevant again after their initial introduction. A plot point without any significance after has no point.
The problem is that there should be no expectations in the first place. Expectations in One Piece are mostly fuelled by fan who think they can analyse the story but actually don't have the element to understand how it really works.
Expectation can be set up by the author writing in plot points that have potential to go somewhere. If the plot points don't go nowhere, it stands to reason to question why said plot point exist.
That's how Sanji fan started to expect a fight in whole cake when the entire character arc of sanji points toward the opposite. Or Zoro killing Kaido, or Luffy killing Big Mom etc. What a character say is - again - not necessarily what will happen. In fact it will most likely not happen.
Sure. Sanji fighting somebody was just hope from fans, but can you blame them for expecting one of the most prominent fighters of One Piece to have a fight? Fighting is one of his most important character traits. Zoro killing Kaido was simply a theory that many hoped to happen for most people at 1st that grew into actual expectations when Zoro declared that he'll cut down Kaido, then proceeded to go to the rooftop. Sucks that Zoro never reflects on why he failed to even knock down Kaido as Zoro did show genuine disappointment in himself for not doing so, but that's whatever at this point. Luffy versus Big Mom was a dropped plotline that didn't even have a proper resolution. Luffy was big on defeating all of the Yonko, yet he wasn't even part of Big Mom's downfall. Even Zoro played more of a part of her defeat than Luffy.
There is what we call legitimate expectation : Expectation created by the storyline
And
Illegitimate expectation : Expectation created by wishes and a poor analysis of the story
In other word : Stay close to what the story say and needs, not what you want the story to be.
Some of us are, and frankly there are still incomplete plot lines and dropped plot points that may never see light of day again, and if they do, many of them have long since past their chance to be in the spotlight and to be used as greatly as they could have potentially been used as the matters some of them pertained to have come to past.