So, nearly 2 million votes were cast in the ballot;
http://www.sourcegaming.info/2015/12/23/496/
Let's take a look at the largest fan-poll that I'm aware of, a reddit survey with 13,000 respondents:
https://www.reddit.com/r/smashbros/..._results_the_smash_bros_dlc_reddit_survey_is/
Note: Yes, I understand sample sizes, which why I know that the pre-emptive "But sample sizes!" argument doesn't work at all. More on that in a bit.
Now, see, this amounts to less than 1% of the total vote share of the ballot. Banjo-Kazooie, Isaac, and King K. Rool all got the top spots. If you made all of these votes into votes for any of these characters,
it would mean that character takes up less than 1% of the voting share.
That isn't an awful number when you account for how vast the vote will be in a contest like this, but you need to take into account something I'll call a "support ceiling", where certain characters have a low ceiling due to low exposure in a large scale public vote.
This is something applicable to King K. Rool, for example: His last appearance in a game sans Smash 4 itself was in Super Mario Sluggers, a game released 7 years ago. In fact, since DK64, he's been relegated to ports and spinoff games from the DK franchise. He's not very recognizable to a crowd of multiple millions, and there's a strong enough divide in that one community that DOES largely recognize him, since plenty of support for other characters exist.
...This leads into the whole "sample sizes" thing, where some people seem to believe that these largely unscientific polls adequately represent the entire Smash fandom of several million. Thing is, forum goers qualify as their own demographic, and using a single demographic as a sample size for an audience comprised of multiple differing demographics doesn't make any sense.
The same support ceiling problem is what kills Isaac, Shovel Knight, and Shantae's chances. But there's another problem.
Dixie Kong is also a character with some level of support, and a character that probably has more mainstream support than King K. Rool does. Tropical Freeze sold well enough (1+ Million units) making Dixie somewhat recognizable. This causes a split in the vote.
This is precisely why no Mario character had any chance of winning the ballot, too. Waluigi, Daisy, and Toad (especially Toad) are recognizable to the average Nintendo gamer, and all could've received votes. Hypothetical:
Bayonetta: 60,000 votes
Toad: 50,000 votes
Waluigi: 50,000 votes
Daisy: 50,000 votes
...Because this ballot is winner-take-all, the latter three lose even though the support for a Mario character was substantially higher. See the same result for Dixie/Rool.
Onto these two words:
"Negotiable"
No reason to believe this isn't in a business sense. Konami's been awful this year and Hideo's request for Snake is why Snake even got in Brawl to start with, so his lack of inclusion isn't anything shocking. This applies to pretty much any third party, potentially. Remember that the level of content that exists for every third-party in this game is different, down to how different the alt colors get to be and how much music each stage has.
"Realizable"
Some people seem to believe that Sakurai just applied this to *insert favorite character here* as a sleight against them as a way to justify his Bayonetta...bias(?)
...Of course, the more likely conclusion is that this word applies to several different things:
-Characters that are too technically demanding.
-Characters lacking in moveset potential.
-Characters that didn't originate in video-games. I.e., Goku, Shrek, etc.
Ice Climbers fall under the first definition, for example. They might have received more votes than Bayonetta did, but technical problems with the 3DS (and possibly the Wii U, due to 8 player Smash) prevented their inclusion.
Theoretically, this could be where Inklings are: Spraying ink would be an integral part of their moveset, and this may not have jived well with the engine or there may not have been a feasible way to faithfully adapt them into Smash.
Wolf
This is anecdotal, but remember when Lucas was announced? Pretty much everybody assumed Wolf was coming back. This is because, leading up to that direct, nobody actually knew if Mewtwo was going to be the only DLC character we got. Lucas and the ballot opened the floodgates on speculation, and the assumption at the time was that "If these two popular cut veterans return, Wolf is clearly gonna come back!"
...If this is the case, a lot of people in the contained Smash community may not have even voted for Wolf, taking him for granted. Outside of forums, Wolf is more or less considered a clone, so... why would he receive a large vote share over X person's dream character?
Where did Bayonetta's support come from?
She doesn't have a split vote issue at all and she seems to be one of the only remaining characters you could choose from. I mean, let's just do a rundown;
-Wolf
-King K. Rool
-Isaac
-Toad
-Waluigi
-Daisy
-Ridley
-Inkling
-Ice Climbers
-Snake
-Banjo Kazooie
If all of these characters are taken out of the running by vote splits, low support ceilings, or conceptual issues in design (+ negotiation issues for third parties) who's even left? The game obviously sold some on the Wii U and has a pretty hardcore fanbase, so maybe they all rallied behind her and that established her placement as the winner of the ballot. Bayonetta had a lot of steam and most people who assumed she didn't have a chance existed in the contained Smash fandom.
Lastly...
Why is there even a conspiracy?
There's no evidence of one, but why would there be one? She's probably going to drive up the game's rating, something Nintendo wanted to avoid so much that they removed Tharja's trophy from the 3DS version. That's a bit of hassle. She's clearly a complicated character, more so than a lot of "fan favorites". There's no real point in inserting her as an advertisement character since her game was released over a year ago.
This entire situation is hardcore denial as a result of broken expectations that formed from the untrue belief that the average forum-goer represented the several million people who purchased Smash 4. I feel like making this topic is necessary because people need to get a grip and realize:
A: A lot of characters aren't that popular outside of communities where people discuss Smash every day.
B: Sakurai isn't out to harm your favorite character. I'm an avid Sukapon supporter, but him not being added is because he's irrelevant, not because Sakurai is out to sabotage the Sukapon fandom.
C: It's a fightan vidya, not your life. It'll be okay, there's no need to carry on a seething hatred for a developer because the ballot didn't go the way you wanted it too.