Ganon is almost easy for Doc?!!? Who's Ganon have you been playin' against? Zelda's not a pushover. Ganon's definitely good. RockCrock and Linguini have definitely proven that, for sure.
There's a huge difference between "easy" and "almost easy". If I said "easy", I would have implied Doc actually had the advantage, but he doesn't. He just merely doesn't have to work as hard since he gets massive reward for simple edgeguards. Like aside from the fact Ganon clearly has better control, Doc can basically win the game off a grab and then a B-air edgeguard. I don't think that takes much work, it just simply requires the Ganon to not be playing perfectly. Maybe the only matchup in the game that takes less work for Doc might be someone like Roy, cuz his aerials suck and he's even easier to gimp than Ganon.
I don't know how difficult it is for Mario to fight Marth. But I can't sit here and troll about Marth being 55/45 or anything close to that for Doc. I mean what about Marth's:
amazing attack speed (f-air that hits at frame 4)
ridiculous attack range and combos
easy edgeguarding
outrageous grab range
Crouching > Marth's air game. Especially if you're Mario, since it's not unreasonably hard to whiff punish Marth with F-smash. Then there's crouch canceling, Dash -> crouch -> D-smash which both Mario and Doc can get a lot of mileage out of, Marth jumping is usually a bad idea for him simply because crouching is so good against his air game.
Marth combos are kinda gay, but he should never really kill you for doing any combos. Just always DI away from him when he throws you or when he jumps (mind the N-air). His edgeguarding is also pretty gay, but as long as you DI well and leave the option open to recover high he rarely should outright gimp you.
Outrageous grab range is also gay, but he's rarely going to kill you off a grab. Shielding against Marth is mostly really good for that reason. Marth's BEST threat against shield is actually D-tilt, which wears down your shield while keeping you in a bad position where all of your escape options can be punished.
IBtw, solution to Marth's d-tilt as Doc = SH - f-air. (Should work/**** for Mario since his f-air combos into stuff)
Soooorta...just the problem with that is everything else Marth does beats Mario/Doc's F-air. Shielding and crouching is good against most of Marth's stuff, but D-tilt throws a wrench in that strategy. You can't really whiff punish his D-tilt on the ground if he isn't hugely predictable with it, which forces you to jump more which is where Marth wants you to be (fireballs and pills keep him from being too braindead though).
Either way Marth isn't actually that hard. Getting in on him is definitely a chore, and his D-tilt is a stupid good move that neither Doc or Mario have a real answer for, but you mostly should survive super long against him with good DI, while gimping him is almost unfairly easy just given how good Mario and Doc's B-airs are. Marth is so easy to gimp he's a character you actually want to use your side throws on to guarantee that he's sent offstage. Mario I'd say does slightly better since his low percent combos are easier to do and since his F-smash gives him a noticeable edge in limiting Marth's air game, while he doesn't really lose the gimp game since Marth is basically done if you tap him once offstage.