Falco's d-tilt is incredibly silly; nearly the same start-up and damage as Samus' d-tilt, but has MUCH less cool down (10+ less cool down), and its killing power is nearly on par with most smash attacks; not to mention it's incredibly useful as a combo tool at lower percents, given it pretty much shares the same frame data as Ike's.
It's actually kind of hard seeing how Samus has one of the best sets of tilts when her d-tilt is completely outclassed by Falco's in nearly every category.
Falco doesn't have nearly the same range let alone disjoint as Samus on his dtilt, there's nothing about it that outclasses her. It isn't strong either unless you're right next to the opponent when you do it, nullifying all its range and safety - at max range the move does 9% and doesn't kill at 200%.
For the sake of argument to prove a point of my own though, let's pretend Falco's dtilt almost completely outclasses Samus' dtilt. You can replace Samus in those sentences with literally any other character that has been suggested as a character with one of the best sets of tilts, except for Little Mac, and remain just as accurate. This is essentially the kind of bias always playing here:
1. "Sheik, Pikachu, ZSS and Samus all have good tilts"
2. "Falco has a dtilt that outclasses all of theirs"
> "How can Samus have good tilts when Falco outclasses her dtilt?"
Any reason for putting Bowser, MK, and ZSS on the list?
Bowser's ftilt is a safe poke with good range and it kills quite well near the ledge. Dtilt is also fairly safe, a kill move and does tons of shield damage + shieldstabs easily if the shield isn't full (25% damage on shield). Also hits the ledge. Utilt isn't terrible so overall I regard his tilts probably better than Ganondorf, although Ganondorf's ftilt and dtilt are better but with both having power and dtilt having safety instead of ftilt.
MK's ftilt kills after the buff and is probably the best sword jab in the game despite not being a jab, the fact that it has disjointed range and is a 3 part attack means quite a lot of safety because you can mix up the timing of the hits and the timing of when you stop the attack if you hit a shield. Dtilt is safe and a faster option by 2 frames and can trip, it just doesn't have a particularly good range but that's basically most dtilts. Utilt sometimes works as a punish/read and sets up for a world of pain with MK.
ZSS' utilt is f3, does 12%, her legs are invincible and it cannot be interrupted meaning it's an incredibly good CQC option that beats out clashes, as well as a great anti-air that beats out most moves pretty much just like Mario's usmash. It also hits onto BF platforms. The only downsides are the long cooldown and the fact that it doesn't hit all the way to the ground, but you have to use it in the right situations. Ftilt is in my opinion one of the best pokes in the game, it basically comes from the same production line as Fox's, Falco's and arguably Samus', Falcon's and Greninja's ftilts where they all have varied range and startup/cooldown but very similar damage, hitboxes and angles. ZSS' dtilt is her weakest one mostly because ftilt outdoes it in so many situations, but it's honestly a pretty good move. More range than probably any tilt in the game (?), hits low, decently fast, only medium cooldown and also makes ZSS hurtbox very low during it. Still can't call it a strong point though.
Anyway, some interesting stats to paint the picture about the ftilts:
Fox: f6-8, total 23, 8%, below medium range
Falco: f6-8, total 27, 9%, medium range
ZSS: f6-8, total 28, 8%, long range
Samus: f8-10, total 32, 9%, very long range
Falcon: f9-11, total 31, 10%, medium range
Greninja: f10-12, total 32, 7%, above medium range
They're all very good and it's hard to say which one's the best, except Falcon definitely stands out as the weakest one. I think ZSS and Falco have the most utility, but Fox and Greninja have the safest ones while Samus has the longest reaching one.
E: I actually can't see why Falcon's is clearly weaker than the others, but I probably felt that way because he'd almost always rather be going for a jab or dash stuff. It's as safe as Greninja's after all.