I think Smash has two major problems holding it back, but weirdly enough they are in and of themselves opposites?
- Smash takes itself too seriously - it builds up even its smallest additions as a bigger deal than they should be; rarely branches out into further merchandise or spin-offs; uses overly dramatic theming unfit for the type of game it is even competitively; and refuses to be self-aware about its fundamental absurdity even when representing comical and "meta" series like WarioWare and Banjo-Kazooie.
- Smash doesn't take itself seriously enough - it only pays lip service to competitive players at best; adds characters based mostly on fan demand and marketability instead of moveset or their place in an "ultimate crossover"; juxtaposes its dramatic story mode with wacky, abstract battles based on promotional PNGs from the 90s; and has strange mechanics meant to give a less skilled player the upper hand that can bleed into competitive play.
