I guess this post is about what are everyones' thought on Ganondorf's worst matchup.. and see if there is a way to counter them. And hopefully learn much from this. To start off, I personally think Pit, Rosalina, and Samus are the most tricky characters to face off with Ganondorf. Pit and Samus both have brutally fast air execution combo from grab/airlaunch and Rosalina has that swole polygon in glitter that just mimics what Rosalina does like they are a pair of synchronized swimmer. I need some suggestions and feel free to leave your opinion on what you think is the hardest matchup.
Pit, to me, is just Link with less annoying projectiles. His grab range is short, and his ground attacks can be punished with proper spacing. As long as you're keeping the pressure on him and spacing correctly, he's not bad at all. Wizard's Foot is a good approach tool when you get too close for arrows, and aerial wizard's foot is great at punishing an air chase. Don't challenge his side-B, as it has super armor, but it is unsafe on shield, so if you see it coming, shield and then punish. If you get offstage, don't use your double jump until the last possible moment, as his arrows can make you waste it.
Samus is a matchup where online lag can kill the entire thing, but in person it's much easier. The best way to approach Samus is by Powershielding her projectiles, but with lag, it's hard to shield them at all. Her roll is bad, but Ganon isn't fast enough to consistently punish it, so rollspam can be irritating. She's quite heavy as well, so rage can work in her favor. However, she is also very tall, so up-air and bair do work on her while grounded. Have to watch out for her up-air while in the air yourself, as it's one of the few moves that can challenge aerial Wizard's Foot safely. Don't let her charge her laser for free. Pressure her. She can't stop your approach and charge it at the same time. However, she can shoot you with the charge beam while you approach, which is what that shield is for. 99% of this matchup ever being bad is due to lag, as it ensures you can't time your shields correctly.
Rosalina is a matchup where you have to be very aggressive while being mindful of her range. You have to know when she and Luma are vulnerable. Do not challenge Luma as she's launching him out, as it is invincible for a brief period and will knock you away. Once you get between her and Luma, try to either dash attack or grab her (flame choke counts), and try to kill luma when she's in hitstun. Be warned that since she has deceptively long range, your usual game of spacing with down-tilt is not going to work, as her dash attack can punish it and knock you away without forcing her to cover a lot of distance. You're going to need to play counter to your Ganon instincts and rush her down. After launching Luma with her neutral B, she is vulnerable, so if you see her charging that, try to get above her or behind her before she lets go. If she lets go before you can get above her, quickly fast-fall and dash attack. Your goal is to get between her and Luma and then cause destruction - she is very light, so killing is not a problem once you get hits on her. If you knock her into the air, do not approach from directly below, as she has a HUGE disjoint on her down-air. Approach her from a downward angle, down-left or down-right, as her fair and bair hitboxes are high, and her dair only goes straight down, so Ganon's up-air can hit her in safety from this dead zone. Don't use any overly laggy aerials against her while she's grounded, as if she shields them or you whiff, she can knock you away and make you have to crawl through the Luma minefield all over again. If you get any moments of respite, try to kill Luma if it isn't already dead.
My worst matchup is Zero Suit Samus. The paralyzer combined with her speed and grab range make her a tough sell, as it's a projectile that holds you in place when it hits you, and she has guaranteed grab combos into her up-B, which kills. You have to time and space your approach perfectly to get any hits on her. However, if she plays aggressively, she is easily punished, and she dies at very low percent, so if you can get the hits, you're doing great. Ironically, a trick I learned from the AI in this matchup is that if you shield a paralyzer at mid range, you have time to roll toward her and still make a punish as long as you do so IMMEDIATELY after it hits your shield, so keep that in mind. Safer to spot dodge at close range.