I just hope that next month at D23, they announce the release year. Not because I think they should show it, but so people would stop making those stupid jokes like "Kingdom Hearts 3 releasing in 2030" and such.
A lot of people make the joke of Union X where you apparently 'need' to pay to win... I haven't spent a single penny and I got tons of powerful medals with guilting such as Illustrated Terra, Boss Marluxia, HD Axel and Larxene A. So no, you don't 'need' to pay, cause otherwise you're not playing.
Everyone who knew Sora forgot about him due to Namine affecting his memories and those connected to him.
Aqua states in 0.2, "Not even memories are safe from the darkness."
(Continuing from point 2) They might be be hinting that staying in the Realm of Darkness for so long can make one lost their memories, especially with Ansem the Wise who had forgotten who he was and where he came from, though it could have been just a side effect of the explosion in KH2.
I think one of the reasons why a lot of people don't want these characters to return is because they believe it's the same as reviving them from the dead, when in actuality, they never died.
Another reason I think why people don't want them to return would be that it would lessen the impact of their 'deaths'/disappearances. While it mostly depends on one's personal perspective, I believe it doesn't make the sad scenes any less sad. The ending of KH1 still saddens me, even when I know that Riku and King Mickey make it out of the Realm of Darkness in the very next game.
The fact that these characters don't die is a good thing because instead of having them gone just like that, they sleep in hurt, suffering, pain and sadness that pushes these characters forward. While Axel returns as Lea in DDD, it doesn't lessen the impact of what he was willing to do in KH2; his actions showed that he wasn't just a heartless entity, but rather someone who was willing to give up their own being (or non-being) to help others. And because of these actions, Lea is now pushed with them and can now be a part of the team.
These characters have suffered more than long enough, whether it was by choice (such as Xion and Ventus) or by chance (such as Aqua and Roxas) and they deserve something:
A second chance.
They deserve another opportunity; the chance to be their own person. Sora himself sums this up perfectly in DDD in one sentence when encountering Roxas; "...you deserve as much as I do to be your own person."
Some people would say that their job is "done."
...What 'job' exactly? Saying that Xion, for example, shouldn't be saved because "her job was done" in Days is like saying that Riku should have stayed in the Realm of Darkness because "his job was done, he closed the door. Let's, y'know, NOT try and help get him out of there."
These characters' return is something that has been hinted/foreshadowed all the way back since BBS and has been hinted/foreshadowed again in Coded and DDD. Ansem the Wise, both in BBS and DDD, states how Sora can help return these characters and give them a new beginning, "their birth by sleep." Half of KH3's story (as far as we know) is to help return these characters; it was the main reason why Sora and Riku were tasked to unlock the Sleeping Keyholes, so they could obtain the power of waking.
Their return was the whole point of these cutscenes:
A person can say all they want about whether or not these characters should return, but I treat them like actual people, not some lifeless toys or puppets or props. If a person can be given a second chance, they deserve it.