It has been a while, and I played Brawl, but if Captain Falcon is not significantly different from his Brawl iteration, then one glaring weakness of his is his difficulty in being precise with his rushdowns from air to ground when the opponent is below him, especially when the opponent is near a ledge:
Exhibit A (air speed): Captain Falcon boasts great air speed, however this can work to his disadvantage, as an opponent who plays evasively with proper timing and rush reads can cause him to overshoot. A skilled Falcon player would know this and try to control their horizontal movement while on midair offense. This can be tricky for them, however, because...
Exhibit B (forward air attack): ... The player has to input in the direction of his approach on the control stick in order to execute Falcon's strongest (if I remember correctly) midair attack, whose sweetspot HURTS. Fortunately the sweetspot is pretty high up on the knee, and is not out for long, so the player has to implement a proximity game to line up premeditatedly, or rush from a long distance away at high speed, both methods are exploitable if they are on the front of the opponents mind. Also, in order to excute the move, the player must momentarily sacrifice a reverse input on the control stick, which together with Falcon's air speed and already difficult to land knee, allows the forseeing opponent to slip underneath with a roll.
Exhibit C ( down air): This happens very quickly, has limited area of effect, and results in exploitable landing lag after a short hop, again presenting a problem for opponents passing under Falcon.
There would be other exhibits, but to cut to the chase, There are too many faults in his aerial moveset pertaining to the interaction of his small hitboxes, high air speed, low traction, and awful short hop properties that contribute to problems with what I call rush control, and forces Captain Falcon to approach from a considerable height in the air, still rendering him quite predictable. His specials are not safe against overly defensive strategies, so he mostly must rely on standard attacks, the hardest to stop of which are executable on the ground. So my opinion is that you should focus on baiting him into approaching from the air so that you can outmaneuver him from the ground, watching for missed attacks, which Captain Falcon is prone to experiencing. Just beware of his back aerial, which he easily resorts to in the event you are behind him. I must confess though, this post would be somewhat speculative, primarily being sourced from my memory of the 'feel' and frustrating aspects of playing the character.
