Its funny that charge shot is brought up, considering its like, the only charged attack that can't be charged in the air, making it even more situational to use.
Add in the fact that a good chunk of the cast has reflectors or other ranged counters as well, one of Samus' best tools in FFAs (and 1v1s), is made significantly less viable. If I'm on the sidelines trying to use charge shot to net all my kills, not only are my (casual, by the way) opponents quick to use their reflectors, but I also become the target player. With weak grabs, rolls, and standard attacks, Samus pretty much suffers the same in a FFA. IMO, Samus is designed to make the person playing as her frustrated.
Compare this Samus to Melee and PM Samus (who is better in nearly every aspect) to SSB4 Samus, and she does just fine in FFAs, but is far from overpowered in these scenarios. I mean, has anyone else noticed Samus dominating FFAs so much in previous smash games?