Thank you! I can't tell you how many people I've seen who are utterly convinced that their favorite game deserves to be referenced in something like the final boss or what. Everyone wants this to be Kirby & pals or Mario & pals. I can't believe Bowser was the adventure boss in Melee. THAT was a glaring oversight just as much as pichu. I really hope this game has more internal consistency than Melee.
While I agree with this "no final bosses from any series besides Smash itself" thing, I just need to point out that having a giant Bowser as the Adventure final boss wasn't all that weird. Just think about it, he's the main villain from Nintendo's biggest series. He doesn't really represent Mario in there, he represents Nintendo villains.
I don't really think of that giant Bowser as a real boss in Melee anyway. I think the real boss was Giga Bowser. And he's a majorly buffed version of the main villain of Nintendo's biggest series, as I've said before. I find that to be a very appropriate boss.
Just wanted to point that out again because of the whole "internal consistency" thing you said.
...huh. Well, so far we have the hands of the kid playing with the toys/trophies and a majorly buffed version of Nintendo's main villain. How DO you make a new boss? The hands will obviously still be there, but having them as the FINAL boss again wouldn't be interesting at all.
So here's my suggestion. How about some weird shapeshifter boss? I mean, having a boss that could take forms of different playable characters would be pretty cool. Of course, he/she would also have more strength, agility, weight...
Have the boss look a little bit different, too. Just give it red eyes and make it black, but not pitch black like Shadow Link in Melee. You could still see its facial features and stuff, but all colors would be black.
I dunno, Nintendo uses the "dark version of whatever character" thing a lot.
And have its normal form (has no attacks, but changes into different characters) be a simple floating black ball (maybe with the Smash emblem on it), because the Smash-only characters are always very simple concept-wise.
I dunno, I like the idea.