Olimar is somewhat similar to Snake and Diddy, they all have beastly Ground game but get destroyed Off-Stage.
Snake's biggest weakness is his recovery but I would hardly say either of them gets destroyed offstage. Especially not Diddy.
Snake mains generally know when you get knocked off you want to regain momentum and go high as soon as possible. Try to stay away from a cypher grab. C4 tech when things get bad. Grenade break WOP assaults. Aerials are pretty risky unless they come after a grenade break but a well placed fair or bair (with it's huge head to toes hitbox) can turn the tide in a second.
And Diddy only really hates the air when his recovery is hit because it doesn't slow down again unless it's timed right or momentum regained with a side-b. Other than that he can basically recover from anywhere on the stage. Has Peanut popgun for projectile disrupting edgeguarding (not only for attack opponents jumping out but full charged blasts work similar to Marth's Shield Breaker)Side B as another jump option(great for momentum regaining or simply grabbing an opponent) two quick aerials, two spikes, wall cling and jump talents, and the Up B has a weird property on it when DI'ed into objects, he doesn't bounce off. He can get spiked out of it and glide right around a stage and make it back.
ICs were the same, they had 25:75 against MK at first, now it's 60/40 to 50/50).
The 25:75 (which I don't recall o_o) was mainly based around how easy it was for MK to break IC's up and destroy the other. Then came shield angling. High enough to auto cancel it? It won't shield stab, low enough to shield stab? You will get punished severely if you don't.
Snake will never move down. You don't need to be fast if you can grenade camp. Though his only good aerial is nair, his ground/camp game is amazing. Speed =/= good.
Snake doesn't even need to grenade camp. It's just the tactic that has the least amount of risk. Yay nade dropping!!
And Nair is his most useful aerial. If you catch a down throw near the edge, just pray he doesn't dair. 35 damage with kill power. Bair is not a kick, it's a body slam, he can drop on you jump into you with or attack you with, no need to RAR, and ofcourse kill power. Utilt lover? Got em in the air? Uair will finish them faster than Utilt (ofcourse since they are closer to the top) and auto cancels when shorthopped (same as bair). And fair is the spike. Great range, power, and priority. If you see Snake doing this and you can't air dodge in time-- that's probably your stock. It even trades with the Shuttle Loops huge disjoint. And for poops and laughter use it for a little boost in your jump(similar to Peach's B). You can even go around some stages without c4 using it.
Situational yes. But all aerials are, you're not gonna jump over IC's head with MK and spam uair no matter how good it is.
Oh and for Marth I think he goes even with both DDD and Snake. Snake for the advantage when he has the port. The only reason they are even label as they are now is because those two can simply put damage on him easier than he can them. Shield Breakers, uairs, and grabs always serve me well in the MU though. DDD's don't like being grabbed as often as they try to. And Marth and MK like Snake offstage. UpB into cypher with dair, fair, and nair options are lovely.
The Marth v MK matchup can't be as bad as we have it now. Offstage we know--MK's greatest area is Marth's worse area. But somehow Marth is A rank(not tier-- this data pertains to tourney wins) with more wins than Wario who goes even and is a rank above him in ranking and tier. Not only that but according to the Amazing(he really is) Ampharos' data he's viably solo, as he has won multiple times alone.
With a 65:35 against the most popular character in the game? MU rewrite time nao plz.
