Those comparisons are bunk. Wolf's fsmash often doesn't link into the second hit properly, so you can't use it reliably when the opponent is right on top of you.
I havent noticed the second hit thing, I dont often use his fsmash. Is this due to SDI? Fox's uair is very susceptible to SDI in melee, for what its worth.
Mario has only two especially good kill moves: fsmash and fair.
Fox doesn't have many true KO moves either. Fox doesn't have an aerial that is anything as powerful as mario's fair. If you land a uair on someone on the ground, it doesn't KO until well above 100% (I would estimate around 120% for average characters, in melee ganon could live past 150%). When you uair out of an uthrow, you are hitting them when they are already well into the air so it seems like it has more KO power than it actually does.
Most of fox's strength in terms of killing efficiently lies in him being able to slowly push people off the stage and keep them off. His bair and nair don't really KO but they are relatively safe on hit and have good qualities in their knockback, as well as a shine to get people off him (and pushes them away - often towards the edge).
I don't think its a problem to allow a character to have both methods to edgeguard as well as have true KO options. In most cases, I think a severe lack of one or the other is a bad thing.
Lucas' has pretty poor range.
Lucas' fsmash is weaker than ness', no? I havent landed too many, to be honest, but I really thought it was too weak.
Sheik's usmash is trickier to sweetspot
But she has guaranteed setups and the sourspot is significantly better than it was in melee, and even then it was a useful KO move.
Pika's is easily punishable even at high percents if you don't hit with the strong hit, something that cannot be said of Fox's.
Was this changed from melee? In melee, the sourspot wasn't bad at all. It killed 20% or so later but still combod and landing the sweetspot wasn't anything other than a minor precision barrier. On hit, pikachus sweetspot usmash was the strongest uncharged usmash in the game.
Let's also bear in mind that Fox's usmash combos from a "frame 1 full coverage hitbox with invincibility that can be jump canceled on frame 4" on a large portion of the cast, regardless of percent.
But it doesn't actually come up that often in melee metagame. Drill is susceptible to SDI making it unreliable to combo into shine. Nair can be DI'd into the air which allows the opponent to dodge combos -- landing on the ground after being shined in the air results in no hitlag when you land, or thats how it was in melee (to my knowledge it is the same).
Here is an example of PPU getting a free grab off SFAT by abusing this. The shine can also be SDI'd away which makes it hard for fox to a) reach you and b) predict/react to which DI you will do in order to follow up properly (fox's shine has much less hitlag than falcos; it isn't reliable to hit confirm with).
TL;DR, I hold that Fox does have a KO move, and its definitely good/viable, but I don't think it is something that is overpowered or a design flaw; if other characters lack killing power or other traits they should be buffed so that isn't a problem instead of gimping characters so they aren't as versatile.
