Considering both Hyrule Warriors and Mario Kart 8 have had premium content adding extra characters and features to them after launch, there has been some concern that the upcoming Wii U port of Super Smash Bros would be the same. However, if that was something you were genuinely worried about, you need not have feared, as developer Mashiro Sakurai has now come out and denied the rumours.
"I understand that DLC could add a lot to the appeal of Smash Bros. and I appreciate that a major part of the excitement for these games come from which characters will appear in the roster, so I think fans could really enjoy DLC that could keep this excitement going," he said (via ). "However, I think there might be criticism that we are cutting up content to sell characters one by one, or that we are adding things later that should have been there from the start."
That is something that Sakurai certainly isn't doing. There isn't a single aspect of the game that is being worked on for post-release, at the very least until after the game has shipped.
This is a great statement to hear from a big developer, as it's become all too common these days for companies to begin working on DLC while the original game is still being fine tuned. It could easily be said that that was the reason so many are coming out with glaring errors and problems.