I already checked it out and said I enjoyed the concept. I would prefer a story that plays on SSB64's concept of the worlds and characters of Nintendo being but a child's plaything, but for an SSE sequel (which I'm normally against), your idea was excellent.
And if you refer back to an old post, I might as well re-post my selection of ideas for improving Adventure Mode (which most people ignored or did not see).
[COLLAPSE="Improving Adventure Mode"]
Improving Adventure Mode
Make Adventure Mode Unlockable: Adventure Mode should not be available at the start. Instead, the mode would be a reward for unlocking all of the hidden characters in the game. The intention of this move is mainly to prevent the mode from becoming a cheap, easy way to unlock all the characters as it was in Brawl's SSE. However, the move would also give players a very big reward for putting in the effort to unlocking the characters - they could now see those characters in action in an awesome storyline. Also, you can get to experience the classic and memorable "Warning! Challenger Approaching!" screens more than you probably did in Brawl.
Replacing Adventure Mode as a starting mode would be the old All-Star mode. Yes, the mode will begin with less characters to combat at start since you haven't unlocked anyone. But as you unlock characters through various means including this mode now, those characters will be added into All-Star mode, and the mode will become progressively harder and longer. I have more ideas for this mode, but the topic is Adventure Mode.
Improved, More "Nintendo-ified" Story: I don't need to expand on this idea since it's an obvious improvement most people agree with. What I will do is link to
this man's excellent proposals for a premise for the Adventure Mode storyline; he has many amazing ideas. One idea I would like to repeat from Hex's ideas is the increased use of humor in the story. This is a game featuring a bunch of odd video game characters thrown together onto stages and set to battle each other; it doesn't have to be serious about itself all the time. For a fun example, Ness could try to use PK Fire on an enemy Wizzrobe in a cinematic, only for the Wizzrobe to reflect the attack with magic. Ness dodges, but Luigi isn't so lucky and seconds later is panicking with flames licking off the back of his pants.
Stories & Gameplay Individualized by Characters: Suppose you choose Adventure Mode in the menu. Then you enter a character selection screen and choose your character like any other fighting mode. Then you enter Adventure Mode, but you'll only be playing through the eyes and experiences of your chosen character. For example, you choose Mario. You'll then only play through the levels, fight the bosses, and witness story events that Mario encounters - you will not be distracted by what Pikachu is doing on the other side of the world unless it directly relates to Mario's story. To put it simply, you'll only experience that character's slice of the story when you choose that character.
The point of individualizing the experiences down to each character is to increase replayability. No character will traverse the exact same terrains or experience the exact same events as another character. Some levels and bosses would be events exclusive to certain characters which the other characters are not going to face. Players will be encouraged to experiment and play with all the characters on the roster to experience the full breadth of Adventure Mode. The individualization would also add greater detail to the storyline. Falco is not going to react and feel about events the same way Ness will, even if they meet early on and stick together for much of the story. With individualized storylines, you can explore the personalities of each character more and deepen the overall over-arching story.
There would points in a character's part of the plot where you cannot progress further until certain requirements are met, since I don't want players to end the entire storyline with one character in one playthrough. The requirement is simply that you play as other characters in the roster and play through their stories in the mode up until those "No Pass" points; after a couple characters or so, you can continue with your own character again until another point in the plot is met, or until you reach the end of the Adventure Mode storyline for your character. You will not be required to play as
every other character to finish Adventure Mode with your own character, but a reasonable number.
Metroidvania Level Design: If you've played the classic Metroid and Castlevania titles, you are aware of the immense open-world design of the worlds in these games. This same open-ended level design, where every part of the world could link seamlessly to another, should apply to levels in SSB4's Adventure Mode.
For example, you're playing as Link in a forest level. While running across the forest floor, you notice a part of the ground with recently dug-up soil. You jump and use Link's Dair to smash through the weak soil and fall into a cave. Traversing this cave leads you outside to a grove with a Sky Cannon from TP. You can use the Sky Cannon to launch yourself up into Skyworld and explore the Skyworld level, which you may not even explore through in Link's main storyline.
Almost every level would link up with others in some way, and you, the player, could discover all the caves, chambers, and levels that connect them all together. A world map for Adventure Mode would only still exist for convenience, now that a player could technically travel most of the world with in one playthrough.
Limitations to exploration still need to be applied. These limitations would be implemented by way of
character-specific obstacles (thanks to KumaOso for inspiring this idea). For example, there is a crawl space connecting two areas that only characters with the ability to crawl can use. For a more character-specific example, a certain switch on the ground is only activated by the power of Nayru's Love, or you need Pit to strike an otherwise unreachable target with his bow. Also, any additional levels you explore with a character do not add to that character's story; the levels specifically part of the character's plot are the only ones contributing to that character's plot.
BTW, the Metroidvania level design also means there should be plenty of
secret areas. These secret areas could be very unique; for example, what if Mario discovers a hidden door that leads to a
Super Mario Sunshine-type platforming challenge area?
Board the Platform levels could be implemented as secret areas in Adventure Mode; once you discover a certain number, you unlock
Board the Platforms as a Stadium mode. Another secret area could be a hard-to-find cavern that is the underground home of the NPC Muddy Mole (more on NPC's later).
Unlockables & Secret Goodies: Adventure Mode should be littered with ennumerous unlockables; trophies, stickers, music CD's, even new stages and game modes. Some unlockables are the rewards of simply completing a special level or boss encounter, or for completing a side-quest from an NPC. But most unlockables are hidden in the nooks and crannies of the world, waiting to be discovered. Replayability would benefit enormously from the scouring of dedicated players searching for all the unlockables.
Cameo Appearances from Non-Playable Characters: Marth and Caeda sharing a tender moment before Marth embarks on his quest. Seeing K.K. Slider at a barren train station performing the K.K. Western. Rattatas darting through the grasses in a prairire and Kokunas hanging from branches in a forest. Waluigi appearing out of nowhere to troll Luigi for a second. All of these characters save Marth aren't necessarily going to be full-on playable characters, but they could still have their little bit of stardom by starring in cameo appearances in cinematics and levels in Adventure Mode.
I understand the complaints of some that it would be disappointing to see their favorite characters only appear temporarily and not be full-on characters. However, a cameo appearance in Adventure Mode's story is better than just a trophy recognition or nothing, and supposing Adventure Mode is unlocked the way I suggested above, you would know who's playable and who's not when you start up Adventure Mode.
Side-Quests: Side-quests would either be given out by NPC's you encounter or would be passive activities you could participate in on your travels. These side-quests would be kept relatively simple in concept, as there's no need for a quest-organization system.
For an example NPC side-quest, Ness encounters a Nintendog in a forest, lost and without it's owners. Ness can choose to interact with the Nintendog and then accept or decline to help guide the Nintendog through the rest of the level to it's Mii owners. Once returned to it's owners, the player would recieve the reward of the Nintendog Assist Trophy for normal play. The initation and end of the quest could either be achieved through cinematics or with subtitles and basic "accept quest/decline quest" choices.
For an example "passive activity", Samus could be venturing through an ancient ruin system and notice unique runes on parts of the ruin's wall. Samus could interact with the runes and use her scan visor to translate the runes and discover the history of the ruins she is exploring with each deciphered rune.[/COLLAPSE]
). And it all depends on choice. If you want to go with Shiek or Peach, or if you want to cross the dark river or not. And the ending is different, well to an extent. You will be cheering along with a 5 characters you sided with the most, and they'll show a special cutscene featuring each character. Like Link leaving Hyrule to find Navi (MAJORA'S MASK).
But i highly doubt that Victini would be a playable character... 
