SPOILERS of this movie below! (along with SPOILERS of these movies).

That said, let the SPOILER DELUGE begin!
Uncle MythMan says ...

William Turner Sr. WILL bring balance to the force when Junior defeats the dark side and becomes emperor of the Flying Dutchman! (and no, Elizabeth Swann-Turner isn't his sister ... yet ...)

I might feel 'guilty' about the following spoilers; but a) being without-shame makes it impossible for me to know how much is 'enough to suffer "guilt" for,' and b) these 'discernments from the movie's events' are too complex to really fit with the movie's story if you haven't seen it (and thus 'spoiled' yourself already lol).

At World's End delivers all the characters (of Pirates of the Caribbean first two installments, Curse of the Black Pearl and Dead Man's Chest) to their final fates:

• Governor Swann raised his daughter well enough to get as far as she did, and thus "be at peace."
• Calypso is truly free, and her heart is truly reunited with the heart of ...
• Davy Jones, who–having finished his term of service–will spend the rest of time united with his heart's eternal mistress.
• Lord Beckett rests well, knowing that "good business" continues.
• Elizabeth Swann-Turner honors her father well in her service as prime-royal of The Nine, and will surely continue to do so in her protection of the heart of ...
• Will Turner, whom Elizabeth keeps from becoming a monster if he visits for one day every ten years. For Will, that 'day every ten years' is the one that keeps his dreams happy as he fills the 'Flying Dutchman'-post as Captain over ...
• William "Bootstrap Bill" Turner, whom Will saved (from debt to the Dutchman) by dying and letting dad cut out his heart to replace the one pierced by ...
• Captain Jack Sparrow, who is just as undead as (and possibly more undead than) the rest of the pirates, but who has no crew, no boat (to speak of) and no real purpose in the future except "being a pirate."

I don't see any 'worthy' sequels happening in the immediate future (I have a couple good ideas that would be good years-and-years later, but I feel a story so-well-tied-together deserves some time to give credence to the mythical completeness).

Perhaps some prequels would be worthwhile (either as miniature features in the surely-impending box-sets, or as "as many features as producers'll pay for" in the next few years).

I foresee the Pirates of the Caribbean-movies becoming the next James Bond-style series (much like Batman seems to have been)—Jack-Spare-O 7?