Trailer analysis:

So I wonder. At the initial Switch conference of January 2017 when they introduced the hardware and the features and the first games and so on, they mentioned the paid online service for the first time and stated it would launch sometime later that year. This didn't happen, its kick-off got delayed a few months. Later, this still didn't happen, online is still free today and is supposed to change that way in september.

Could this be related to Smash? Could the release of Smash be the cause of the online delay? If your first thought is yes, then that means Nintendo had planned to release Smash already in 2017. Imagine how much of a shortage THAT would have caused!

Speaking of the shortages, could THEY in turn be a factor for the Smash delay? Could it be that Nintendo didn't want to put even more pressure on the already unlucky situation? If yes, that would turn all this into a strategic release rather than a delay. Much like Odyssey had been finished much earlier than October already but they held it back on purpose. They may use these last months now to polish everything up and also to let some other, smaller games have some time to shine like those Wii U ports.

Ok so ill do another top most likely character threads in the near future like i did for ssb4!

Obvious pick for 1st place would of been inklings but they are already confirmed! Lets see who will it be! Stay tuned....

If you're asking me to give some counter to the argument that "it's possible a team could have gone immediately from making one game to working on the next," then as I've stated before, I don't care to counter it, because it's impossible to do so. Obviously, it is within the realm of possibility to make a game with that little time between installments. The question is not whether it is possible or not, but whether it is likely. You've yet to give any argumentation as to why this is likely the case.

As for Smash, I believe Sakurai only joined development following the completion of Kid Icarus, but Bandai Namco and internal Nintendo staff were involved as early as the game's announcement in 2011. The Fire Emblem example doesn't really apply since Fates' development was finished and the game was launched in Japan in 2015; it only arrived in the US in 2016 because FE has had absurdly long localization times in the past. Three years is more than enough time to put out a remake and a new game...and that's even assuming that we do still end up getting FE16 this year.

Then why even bother spending the money at all? Why spend money on trailers for Cloud, or Bayonetta, or Megaman, or Snake? Do you really think Nintendo just spends hundreds of thousands of dollars on trailers just to "surprise" people? No, they don't. They're a corporation, with profit interests, and anything they do related to marketing will be done because they believe they can make money off of it. This is no exception. Nintendo invests money in making those trailers because they think it will help sell the game, the same way that other game franchises much bigger than Smash, like Mario Kart, GTA, Call of Duty, etc, all use trailers as well. Companies don't just put the time, effort, and money required to make trailers like that for the hell of it.

Namco were not involved until after kid icarus. Sakurai said that absolutely nothing would be done till after kid icarus uprising, that included who was developing the project. 

Do you know if this actually wound up being the case, or was just something Sakurai said in the category of "I'm definitely not working on another Smash game?" I could swear I heard that some development had begun prior to KIU's wrapping up.

Regardless, another point is that it would mean jumping straight from developing one Smash game to the next and operating under that same high pressure environment he's spoken out against consecutively, which also seems abnormal.

Well I'm not claiming it to be true, it's rather just food for thought. But what about it makes you say no? Maybe the development time between the last entry?

All the information I've seen has said that absolutely no development had begun on smash wiiu before kid icarus was released. Sakurai even said that it was a mistake announcing that the games were being made in 2011, because they had done nothing up to that point.

The main point against it being a port is that they didn't treat it like a port. They treated it like a  brand new game. If it was a port they would have shown gameplay. Lack of gameplay suggests that there is something new. Every port nintendo has announced has had at least some gameplay.

I'd argue the inverse; with a port, there isn't a significant need to show gameplay, since people will be pretty familiar with the product already. You don't need to remind people what Smash 4 plays like. With an entirely new game that's at most 8 or so months from launch, you'd want to show gameplay, or at the very least, more than just a mysterious blacked out shot of characters that's probably better described as a teaser rather than a full blown trailer. If it is a new game, it would presumably be Nintendo's biggest hitter of 2018; why keep so much information under wraps this early before release? It doesn't make a whole lot of sense compared just about every other big name Nintendo title I can think of. 

What was the last Wii U port Nintendo introduced with a cinematic CGI trailer?  
What was the last Wii U port that Nintendo didn't explicitly say was a port?
... where Nintendo just left a placeholder year release (2018)?

They've been tone deaf in the past but never to this is extent. No one should be expecting a port.

Nintendo announcing Smash and releasing it the same year isn't that bizzare. Mario 3D World comes to mind, revealed E3 2013, released that holiday.