To answer your operation moonfall question, they said that it's a possibility. They want to continue on the next Zelda before they do another remake. IMO, they won't make Majora's Mask. People are becoming way to demanding and are actually being extremely rude to Nintendo. It really angers me...
I find that he grew more mature as the game progressed. You find out, that really, he's a nice guy with a good heart. He's all grown up!! *sniff sniff*
You know it's going to happen, eventually. All good things must come to an end. Be happy that this series was even made, don't whine because it's over.
I don't think Hyrule Castle is even considered a dungeon. We've seen many dungeons through out the Legend of Zelda series. If it doesn't have a lot of puzzles, a mini-boss AND a final boss, sorry, but it's not a dungeon.