You're going to have to get used to it, this isn't Melee where the whole population concentrates on basically five characters, there are still a majority of characters in PM who don't even have a single top player representative. Let alone several.
I agree with snake. I've played a bunch of games with @
Professor Pro
when I hosted him at Republic of Fighters 3 and felt like I did a bit better than I deserved to, more often than not putting him last stock when I'm not nearly a top player. He still won 38-1 so it's possible he sandbagged until the last stock, mind you :V
I think he'll agree Ivy wins it, at least slightly. We can detonade nades, mortars and mines safely with our disjoints, and he's the right weight/falling speed for our combos while he has trouble landing combos on us. Both characters struggle at edgeguarding each other, so that area does not matter all that much.
I don't think mewtwo is our worst matchup, because Marth exists. But yeah it's bad xD