Based on the videos streamed so far, it seems to me like we may end up with four empty slots in the roster once all of the characters have been unlocked. This leads me to speculate that there might be four more characters that are released with the Wii U version that are then downloaded to the 3DS through the Wii U menu option.
Comments?
[Update]
Some guy's claiming this same thing but saying he has a source: http://www.neogaf.com/forum/showpost.php?p=129524882&postcount=14153
Also, patches have been confirmed for the game:
http://smashboards.com/threads/smash-wiiu-3ds-miiverse-daily-pic-september-12th.367424
Here's a quote with a good point against this idea:
http://smashboards.com/threads/smash-wiiu-3ds-miiverse-daily-pic-september-12th.367424/

Comments?
[Update]
Some guy's claiming this same thing but saying he has a source: http://www.neogaf.com/forum/showpost.php?p=129524882&postcount=14153
Also, patches have been confirmed for the game:
http://smashboards.com/threads/smash-wiiu-3ds-miiverse-daily-pic-september-12th.367424
Here's a quote with a good point against this idea:
http://smashboards.com/threads/smash-wiiu-3ds-miiverse-daily-pic-september-12th.367424/
The argument against this quote is that it's Nintendo, not Sakurai, making these calls and that the interview is from June of 2013, before January 2014 when Iwata announced that Nintendo was looking into new business models to raise revenue for the company.http://www.nowgamer.com/news/1972435/super_smash_bros_the_difference_between_wii_u_3ds_versions.html
"Fundamentally we’re going to have the same characters on both systems," said Sakurai. "If there was a character you couldn’t play on Wii U but you could play on 3DS, or vice versa, that’s rough for consumers."
"So we want players to be able to have the same character experiences on both devices."
The idea behind this is to enable customers to have the same experience regardless of personal platform preference.
"I don’t have a preference whether they own the Wii U version or the 3DS version or both versions," Sakurai told us. "It’s sort of like what I talk about with the game creation philosophy itself – I really want the end user, the game player themselves, to find what they like and really just go with that."
Looks like the game download is only half of the size we were told it would be. This supports the DLC theory.
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