Sean Wheeler
...I don't think Cloud needs additional trophies, music tracks and such to "justify" his inclusion. Cloud being Cloud, as it being an iconic video game character, is good enough by itself. Square Enix is notorious for being very protective and stingy with their properties, which would explain the lack of FF music and anything else. His english VA not reprising his role has something to do with him being part of a union or something, but that issue has nothing to do with Nintendo of Japan. However, I don't see the relation between either of this and Goku's hypothetical inclusion in Smash.
You also overstate Funimation's role in all of this. They have little influence on Goku's inclusion regardless of what they said. They are just a dubbing company in charge of the english dub of the Dragon Ball anime, which is directed towards the US audience. They have no more power than other similar institutes that exist in Europe, Asia and Latin America that fulfill the same role for their respective audiences. Besides, they did it as part of the ongoing meme of wanting Goku in Smash. I doubt that most of his support is really sincere, and its probably just a byproduct of meme culture.
As you may know, getting all of those entities to agree with Goku's inclusion on Smash and then dealing with the publishing rights outside of Japan is a big hurdle that most third parties in Smash didn't have to overcome. Granted, I don't think Goku's inclusion would ruin Smash to the point of making me lose interest in the game but there are also some implications that his inclusion would bring; if Goku joins Smash, that is a line they would cross that they would never be able to go come from. Nothing would stop characters originating from other media to join in as well. That would open the floodgates for Batman, Shrek, SpongeBob, Naruto, Harry Potter, Steven Seagal, Ben 10 and so on. What started as a celebration of video game history will become this convoluted mess of fan fiction fuel that you find in games like Smash Clash and MUGEN.
"But Soul Calibur had Darth Vader and Tekken is going to have that guy from the Walking Dead"
Those are different franchises and are treated differently from Smash.
I acknowledge that things have changed though. Smash started as Nintendo-only characters, then Snake came along and left the door open for third parties to be included. Yeah, I know DB has had lots of titles on Nintendo consoles, but they are still strictly video game characters that have had some sort of connection with Nintendo, while Goku originated from a manga.
For most third parties, their inclusion in Smash also serves as free advertisement, to gain revenue and to give their series more exposure, but DB games are already more profitable than most of the franchises in that game. I'm sure Sega, Capcom, Konami, etc. are more than happy to let Sakurai use their properties, but if they were to include Goku, Toei would probably like for Nintendo to go the extra mile for them to make it worth their while. This is because Dragon Ball is bigger than Smash and one of the biggest franchises of all time across every form of media, so they are not exactly in need of the exposure the other third parties enjoy.
Smash is already going to sell buttloads regardless if they include Goku or not. Most people who want him are determined to get the game anyways. And even if his inclusion somehow causes Smash to move more copies, that wouldn't necessary mean that it would make Nintendo more money. Sakurai overworks himself but I don't see him bending over backwards for Toei's and Toriyama's sake.
Dragon Ball is enjoying a renaissance since the release of the Battle of the Gods movie in 2013. After that, they had one more movie, a show that lasted over two years, two successful (and competent) video game series in Xenoverse and Fighterz, an upcoming crossover collaboration in Jump Force and a movie releasing on December that is picking off where DB Super ended and will likely continue the story afterwards. So really, Goku isn't hurting to have a playable appearance in Smash.
Let Smash be the hall of fame for video game icons, both big and obscure, that it is already rather than devolving into sticking in anybody from other media. And let Goku duke it out with his manga brethren in games like Jump Forces. He belongs there more than he belongs in Smash.
People who want to play as him that badly are better off playing DB Fighterz. Or play a match with Lucario, Captain Falcon and Ryu. They are voiced by the same people who voice Goku, Vegeta and Gohan respectively, they are also brawlers who project energy, so that's the closest you'll get to a DB fight in Smash.