I just realized that a lot of the people mad about representation probably grew up with a Super Nintendo. That console was pretty much the peak/starting point for the series/subseries that the community is hung up about, and most of the particularly upset people are in their mid-to-late twenties. . .
Not that a little more fairness in how the franchises are balanced wouldn't be a good idea, but most of the people who AREN'T upset seem to have grown up with later systems.
I dunno, I just found it interesting to note.
Not a coincidence, it's called nostalgia and the consequent bias that comes from it.
Smash 64 did focus a lot on the SNES and N64, same for Melee. The newer games have a larger focus on the latest eras, where some franchises became less popular (Star Fox, F-Zero) and others began to rise in popularity (Fire Emblem, Animal Crossing). I feel that some older players have difficulties in understanding this, which isn't quite extraordinary, to be honest. We're all a bit like that as we grow up.
Brawl had a lot of Metroid representation given it was developed when the series had a huge rise in popularity and notability. The Metroid Prime trilogy, Fusion, Zero Mission, as well as spin-offs like Prime Hunters and Prime Pinball were all relevant when Brawl came out.
Fast forward to the current decade, Metroid only had Other M as its sole notable game and was a very divisive and controversial title that nearly killed the series due to how much of a disaster it was. For the current generation, Metroid doesn't have as much of an impact as it did back in Brawl's time.
Same for Star Fox, that had Assault, Adventures and Command released in a fairly short amount of time, whereas towards the release of this game, the only notable game was a remake of a title from 1997.
Sakurai does look at current trends when deciding which content is given more or less focus in Smash. Content from all generations of Nintendo games are still present with retro stages like Balloon Fight or Duck Hunt... Likewise, stages from previous Smash games and music bring back the content relevant at each Smash game's era.
Stages such as Delfino Plaza, Luigi's Mansion, Pirate Ship, WarioWare, Inc. all come from Brawl and are derived from games of the GameCube/GBA era. Likewise, most N64 and Melee stages come from SNES and N64 games such as Kongo Jungle 64, Peach's Castle 64, Onett, Yoshi's Island (Melee) and Corneria.
In that sense, each Smash game adds to what was represented in previous games, most of the new content being focused on the current and previous generation. It's evident when most stage choices come from Wii and 3DS titles: Mario Galaxy, Skyloft, Arena Ferox, Reset Bomb Forest and Tortimer Island.
The same is true for most character selection, which is why characters such as Sheik, Lucas and Shulk made into Smash when they did and likely wouldn't have gotten their place otherwise.