Super Smash Bros. for Wii U and Super Smash Bros. for Nintendo 3DS will not receive any more balance patches that make major adjustments to gameplay. Director Masahiro Sakurai confirmed this in a recent interview with Famitsu magazine (via: EventHubs).
Sakurai did say that the game would receive further adjustments to its online multiplayer over time.
Additionally, Sakurai mentioned that, were any glaring issues to be found within the game, naturally, those would be addressed in a future patch.
Source: Famitsu, Smash Bros. Matome