What makes Falcon not worthless is the few moves he has that are safe on defenses. Well-timed N-airs and Jabs are safe. He's fast enough to cross up his opponent reliably, and B-air is pretty safe.
Most of the time jabs and nairs are safe, if your opponent isn't fast enough to punish them. Some characters have shield grabs that are easily fast enough to punish nairs or jabs (the first-hit-nairs can be spaced to avoid this, but then you won't be close enough to follow up with anything). A lot of characters with fast, high priority nairs won't have problems punishing you out of their shield either. Certainly not as punishable as Ganon, but still punishable, and still able to blocked by someone putting up a strong defensive front. Bairs can be good. I can manage strings of them a lot at lower percents as well (if your opponent lands and rolls backward after getting hit for example), but they don't lead to much more than that most of the time.
The 2nd hit of Downsmash is a pretty safe KO move and buffed. Up-B out of shield is fundamentally safe as long as you don't do it against something that is safe on block. U-tilt is a good attack that got an angle buff.
First hit dsmash kills are more frequent really (due to it's relatively fast speed coming out, pretty good priority, and rather deceptive hitbox, which can be used to punish characters using aerial approaches). 2nd hit kills usually happen due to opponent fault, as they'll have to do something like roll behind you or not land far enough away from you, etc, as they should see the move coming out and atleast be able to figure out a way to get past 2nd hit.
Up-b OoS can be useful, against medium to tall characters. Extremely difficult to land against smaller characters that are shorter than Falcon, and requires you to be very close (if you're nearly inside your shielding opponent you deserve to get punished most of the time).
Utilt is **** and is one of his most reliable kill moves in BBrawl IMO, and is what I kill with most often. No complaints about this, except that an opponent who is well aware of its power will make a decent effort to stay away from it, so you don't hit with it too often, although that means that when you do connect it's probably not very worn down so it'll hit hard. But yeah, can't complain about this one. An invaluable tool to Falcon, especially because of its disjointed hitbox.
Now that I think about it, he probably could have used a few buffs on different moves...although seriously. What makes Falcon Falcon is his much improved damage dealing potential. Unlike Ganondorf, he has stuff that can always be used safely on defenses. Although he does require a lot more precision than most characters.
Knees sweetspot easily on the platforms of BF, so the buff there is pretty useful.
He'll increase his opponent's damage at a faster rate, which can be nice, but there are certain situations where it'll be very trying just to get in and get a decent amount of hits at all. The only reason I think it seems to look pretty okay is a lot of matches you see of pretty good Falcons are probably against opponents who are not at all familiar with how to play a real, serious Falcon player. However if he becomes more popular, and more people learn to play against him, I think it will become clear to more people that he's still got some pretty significant fundamental problems.
And even with platforms your opponent's gotta be asking for it to get a knee landed on him
If you can pull something off like an AC dair to your opponent falling on the above platform (no tech) you should get a knee. Otherwise your opponent really has to not be expecting it for you land a knee, or has to make a pretty huge mistake to get punished with it.
I'm interested in what all the BBrawl crew tried in their efforts to balance Falcon though, like if there were anything they didn't wind up implementing (like how the dtilt trip got removed). Stuff like, was a more forward angle considered on Falcon Kick? If it was more like Ganon's and could push people offstage (which, with certain hitboxes on the kick and at certain percents, I think is possible already [with poor DI] but not always). Were any moves considered to be sped up? I can think of about a million uses for ftilt if it came out a bit faster and ended a bit faster (it's not too bad right now, but if it was faster it'd be great for increasing Falcon's range on the ground).