What the? Sing isn't a recovery, her side b is though.
Yea, Corkscrew also is a recovery move, but it isn't Wario's only recovery move. Seriously.
Besides no matter how much skill you have, you can still end up lower than the playfield as any character right?
If you play Wario and let yourself bring into the lower half of the playfield with his insane momentum cancelling, floatiness, weight, horizontal recovery and his whacky vertical recovery, then you're doing it wrong.
Wario has his second jump, the jump from the bike, the fart (only the poot doesn't cover vertical distance) and - if all of that fails - additionally the Corkscrew as last part of his recovery.
Saying Wario's recovery is
bad is like saying Meta Knight is bad at gimping or Snake can't camp.