Well, this tier list is inaccurate. I'd say Samus is mid tier, but I'm being modest. If I were to be honest, I'd say she's higher. Maybe she's still mid tier, but she was low mid tier in SSB4 according to other Samus mains. Even commentators spoke with some respect toward Samus in SSB4. Ironically, ZeRo said Samus was actually good in one of his Twitch streams. That pissed me off after he spoke ill about her before the game was released.
Anyway, from my personal experience using the following characters, I'd say these are at least somewhere in the range of high to mid tier
Mario
Sheik
Zero Suit Samus
Pit (and by virtue, Dark Pit)
Samus (and by virtue, Dark Samus)
Inkling
Roy (and by virtue, Chrom, though his recovery is garbage)
Ness
Ridley (might be low mid tier)
King K. Rool