I am very well aware that otaku-appealing characters would be considered an out-of-left-field pick, and would certainly be surprising to many Smash fans, but how often does Sakurai adhere to our expectations? While I wouldn't say these characters are highly likely in any way, I still think it's worth discussing, as they do have merits for inclusion:
-Smash is no stranger to niche franchises. Series like Mother and F-Zero are unrecognizable to your typical mainstream gamer.
-The otaku community is a significant market in Japan. If you consider the countless conventions funded, or the fact that Fate Grand/order is the highest grossing mobile game in the world, the numbers really speak for themselves on how big it is.
-If Smash Bros is a celebration of different aspects of gaming, doujinshi is one that has yet to be represented in any form.
-I don't necessarily think that every character must have the same mass appeal of games like Minecraft. As I said in an eariler post, there is a clear target demographic that characters like Reimu or Saber appeals to, and is one which exists outside of Minecraft's sphere of influence.
I don't see an Otaku appealing character in Smash, seems niche. I thought we already have characters like that in Smash like the FE cast and stuff like Palutena.
While franchises like Kid Icarus, Persona and Fire Emblem have heavy anime inspiration, their presence still extremely minuscule in the doujin/otaku scene compared to the big names like Fate or Touhou. Here's an article of the top circles (fan groups) in last year's Comiket to give you an idea of the types of franchises that are popular:
https://www.animenewsnetwork.com/in...-holds-the-dojin-throne-at-comiket-94/.135012
And since you mentioned Fire Emblem, why do you think the newer entries of FE are including dating sim elements? These mechanics were solely made to appeal to the otaku demographic, and they are what sell in the current market. So if there was any doubt that the otaku demographic had any real influence on the gaming industry, just look at Fire Emblem and how it became one of Nintendo's biggest franchises.