I'm skeptical of Shadow Blade having utility anywhere in the ballpark of Metal Blade. Can you elaborate?
Today's bold question: Should Samus actually consider Melee Charge Shot against Rosalina? (Between Luma and Gravitational Pull...)
Edit: On the subject of "bad" Samus moves, what about Screw Rush? OoS moves that hit in front of you are rare, and frame 11 isn't bad for a reliable 15% damage. Normal Screw Attack against grounded opponents struggles to do even half that. Also, it kills!
I feel like a Melee Charge Shot set should be included, but only one (if I had to pick one, 3232 would probably be it), specifically for Rosaluma and reflector matchups where it's exceedingly dangerous to throw out a charge shot (though dense is fairly safe if you're not an idiot, just due to how slow it is). As for Screw Rush, as cool as the move is (for being the only accurate representation of Screw Attack, since you have to do a spinning jump to screw attack in the 2D games), I'm a bit iffy on its applications. It's a bit like Aether Drive in that taking it sacrifices a lot of your vertical recovery, in exchange for horizontal which Samus doesn't need thanks to the glorious range of the grapple beam. I could see it having decent aggressive properties, but as a recovery it seems like such a disadvantage that I'm not sure it's really worth it. Much like the Ol'One-Two for Doc, which has never made sense to me unless we're adopting a "screw his weaknesses just give him another strength" rule for that move.
But I'm willing to give 'em (Screw Rush and Melee Charge Shot) some more trials to see if I can come up with justification.
Back on Shadow Blade, I do like how it covers your approach longer due to the backtrack it has, and its inability to be turned against you save by reflector appeals heavily to me. It's certainly not as versatile and powerful as the Metal Blade, but if only for safety for less-confident players, I'd still have one metal blade set.
Later edit after testing:
Grounding Blow on Mac has my approval, but I definitely prefer the Haymaker over-all.
The Ol' One-Two is aight. Who needs recovery anyway?
Melee Charge Shot has uses against reflectors/Rosalina. It still kills around 100 (against Fox on the 3DS version, which is where I tested it), but it's got the endlag that the regular charge shot does, so it's only really for reads/punishes. Still, at least it can't be absorbed. I'd recommend at least one set with it, and if not other good sets are found, maybe two covering the various other options. 3232 and 3211 maybe.
Screw Rush gets my disapproval, though. Nigh-worthless as a recovery (as predicted, the grapple beam does just as well unless you're too close to the stage, in which case any other screw attack is better), doesn't seem to kill as early as the others since I was using it at ground level. I would still run Apex Screw Attack in 90% of situations.