As far as I understand the box art theory, it is that we have two characters left because of the spaces.
And that discredits that one of the spaces would inherently be isabelle, whom we just got.
Nevermind the fact that the 'box art theory' implies that the current art, which features Ice Climbers and Peach, more than the Mario, Zelda, and Pikachu...
If you think Nintendo wants to market Ice Climbers more than Mario or Pikachu, I can consider that a point of view, even if it doesnt make sense for any monetary reason. The box art theory, as far as anyone has yet to explain it in my research, defies absolutely all facts. I understand this community wants to look at any reason to short circuit, but this one just isnt logical .
Last night we had a discussion that pretty much everyone is fed up with the box, so I will keep it concise as possible.
The spaces we can already see aren’t the reason people give credit to the box. The reason is that every 9 characters is in order on the side we can see and then it skips another 9. So, it would make sense(is not proven, but evident) that the characters are also in groups of 9 and skip 9 on the other side.
The problem is that, out of the groups we see, one group ends with Mii Fighter and the next begins with Corrin. Those groups of 9 are each in order by their official numbering as per the official site.
In between Mii Fighter and Corrin, there are only 8 possible characters and is the only part where the pattern is broken. It would leave a space on the other side of the box.
Within that pattern breaking 8 characters, if the space is a character, then it must be an echo. Ryu is in that group. Verg says Ken, so people lean on Ken.
Why would they break that pattern like that? Why would they not just keep it at 9 characters like the rest? Echoes make sense(not proven, but evident).
If that were true, and they are leaving the mock-up open for upcoming echoes, that means there is only one echo left to reveal(might be Ken). If there is only one echo....how do we feel about remaining unique characters after all the reveals so far? 5 unique and 4 echoes as of now. It’s been pretty even. So that’s another pattern we can at least keep in mind.
All in all, there just isn’t enough evidence to come to a conclusion either way and state it as fact. Therefore, the debate is worthless since no one has objective proof.
Out of respect for those who are tired of the topic, I am only explaining what there is to the theory and not debating whether or not I personally feel it’s true.
I advise against continuing the topic further than the basic knowledge of the theory, because it’s been discussed into the ground and it always causes tension.
Hope that helps.