> There was only one solo Sheik in the top 8 of G3.
> Every top level Sheik main was there except Edge and Shu from Japan.
> None of the top level Sheik players were taken out by another Sheik.
vs.
> Two solo ZSS players in top 8
> One of those ZSS playes was taken out by the other ZSS player
> A top 3 ZSS player was absent
In no way do G3 results prove that Sheik is massively overtuned to the point where no character can keep up. She's not disproportiately stronger than next best character or everybody else. She still has a slightly negative tournament record against Sonic and an even one against Diddy Kong too.
If you want to increase the balance of Smash 4 you could probably argue that
a few minor tweaks on her problematic moves are justified. Dthrow angle / cooldown, fair hitbox, bouncing fish frame data, needle storm ... but take it one bit too far and the character may very well fall apart. Anybody remember what happened to Greninja? To this day, even after receiving numerous buffs since, the character has not recovered from having had no more than two tweaks on moves that were perceived as problematic. But really, as things stand Sheik's strength has not proven to be a major factor of imblanace compared to the incompetence of the weaker characters. Buffing them is still the better option.