Hi Axel,
Try looking on
page 14 of the
Wry Mustache Man page for help on marth as we discussed that matchup. I too struggled against a marth and reflecting on it, my struggle against marth came from poor, what I like to call, "Wario Fundamentals," as ordinary fundamentals don't translate well to wario. I can almost guarantee you Marth and maybe/probably ike have bad matchups against Wario (If Ike does win it can't be by much and would only be at a low-level of play imo), but just because the match up is good for Wario, it doesn't mean it's easy. Way too many matchups for wario are like marth v. falcon in melee, it seems like you can never get in and at first the marth will always win in the low-level matchup meta, but when you understand the matchup better in terms of mechanics, frame data, and approach options (or sometimes non-approach options ;D), it drastically starts to skew into your/falcon's/wario's favor.
As for a character like Ike who I play against a lot, my advice is never throw anything out that can put you in a situation to get punished
hard (aka
f-tilt in a frame neutral position,
sh nair is pretty good and
sh hop u-air and
rising f-air in these scenarios), or even
dash attacked since that's now a kill move for Ike. Secondly, a lot of people don't know these things, but Ike is the same weight as Wario and also Ike is a very grab-heavy character. He has frame traps and you have to learn how to DI and not to react out of fear and sometimes going for a read kill isn't worth it because ike tanks hard and will kill you if you miss. As for recovery, your general recovery game has to be strong to not get spIKEd by ike. I'm not going to say recover high or low, because smash requires mixups, but I find recovering high or drifting with air-dodge to help me recover safely. Wario doesn't have disjoints (He actually does) like Ike, but so do other top characters like yoshi, sonic, and falcon (they have disjoints too lol, especially falcon). But what makes him/them great is their ridiculous mobility. I know this top-ike player who throws out short hop back flips because it gets people to rush him and he punishes with back air. He has to work with that, while wario's tools are so much better given that he moves around about as quickly as jigglpuff and yoshi. When you learn to abuse Wario's aerial mobility to bait and punish ike, then the matchup will come clear.
I'm still working on the peach matchup myself, which I believe is also like the archetypal marth-falcon matchup but even more extreme. Also, I would not like to disregard how much of a solid of a character ike is, if the ike you're playing against is as good as you, he can still win.