Yes. Just like Brawl has MK and ICs and Smash 4 has Diddy, Rosy, and Sheik. Every smash game is unbalanced on purpose and will always have an overused character.
Eh saturation is different still in each version.
But it's pointless to argue this unless we look at raw numbers. Which isn't that different at the top with the #1 getting most of the results.
though is scales differently with each game.
MK has the largest gap if you compare him with the next in line, Snake.
PM seems to have the smallest gap, Fox not much better than marth, but this is also considering differing in patches, 3.5 came out in the time frame. So there is some differences there in usage. Though again this is partly due to the fact most fox mains in melee stick to him in PM because he more or less isn't changed that much outside of some nerfs and some new options.
Brawl on raw numbers without looking at context is the worst in terms of top to the rest, though it does smooth out after metaknight a lot better.
Falco rounds out Melee a bit better at the top, but outside of that Smash 4 and Melee don't seem to be that different in terms of usage numbers of the top 8. Though this may change if customs pick up for better or worse.