Smash Bros. head Masahiro Sakurai told Nintendo Power (via Nintendo Everything) that huge character rosters are hard to balance, and that the series would instead go in a new direction.
"It isn't a matter of 'if the next game has 50 characters, that'll be enough'," Sakurai explained.
"There is a certain charm to games that have huge casts of playable characters, but they tend to have issues with game balance and it becomes very difficult to fine-tune each character and have them all feel distinctive.
"In terms of quantity, we've probably already reached the limit of what's feasible. I think a change of direction may be what's needed," he concluded.
Previous games in the series have added roughly ten characters with each new release, culminating in a roster of 36 for the Wii's Super Smash Bros. Brawl.
Announced at last year's E3 Gaming Expo in Los Angeles, the upcoming Smash Bros. game is several years away from release.
The upcoming 3DS and Wii U game will be co-developed by Namco Bandai and Kid Icarus: Uprising developer Project Sora, with series regular Masahiro Sakurai heading the project.
The mascot brawler will reportedly feature cross-platform play between the Wii U and 3DS.
The Super Smash Bros. series, which debuted in 1999 on Nintendo 64, sees Nintendo characters such as Mario, Link, Samus and Kirby together in a fighting game.
Watch a trailer for Super Smash Bros. Brawl below: