I don't mind Sora becoming more heroic. But he act more mature like he was in KH1, in Hollow Bastion and EOTW scenes. It was so goddamn heartwarming to see him in that game, becoming more responsible, and willing to sacrifice himself for others. They never had to make him a goofball. He was just a likable character overall, without overrepresentation.
This ^
It made him identifiable or more "real". He had things to worry about but he actually matured as a person in KH1 taking on responsibilities and learning whats more important to be done.
He started out childish, fully enjoying seeing new sights and just tolerating D&G to accepting there's something only he can do as well as considering D&G true friends.
He was just more "real" in this sense. CoM built on this when it made him borderline antagonistic.
There just is no real excuse for his behaviors on KH2 or DDD. Even if he was made to be look younger in DDD he was still as of the same mind as his actual age, there's no excuses there.
In KH2, yes sure he had less to actually worry about, but he was devolved as a character from being the maturing and responsible kid he was in KH1 to becoming a copy&paste shounen hero and somehow in the transition actually got dumber.
I know Sora was never the brightest but by hell he was never actually stupid, just simple. He grew up on a, from what we can tell, mostly non-technological world so his more simplistic personality is expected. (especially in regards to computers)
If Nomura really wants to address the issues of his character he needs to take a hint from his KH1/CoM self and build on that.
he was able to act like how he most likely would have acted in the first game if the darker elements were taken away.
Except even before dark elements came into play, which was the first bit of KH1, Sora didn't act anything like KH2/DDD Sora. Hell, if anything, Data!Sora is a more faithful representation of how he'd behave in normal situations lacking threats.