I'm not disagreeing you about reliability. I agree that unreliability is bad, and that it makes the game slightly less fun for competitive play.
What I'm saying is that it's mostly reliable, and I don't think it's worth messing up Pichu's appearance to fix something so minor. I'd support buffing Samus's jab or adjusting Pichu's hurtbox just enough that that jab connects. But I definitely don't support taking it as far as Bent took it.
Yes, Brawl- has some silly-looking victory/defeat animations, and I'm personally a fan of the "Minus art" character portraits. However, the characters themselves are meant to look good.
This does not look good.
that might as well be tripping
Tripping allows your opponent to tech chase. Whiffing a jab means your opponent takes a little less damage. If they somehow predict the whiff, they can respond with a weak punish.
Besides, have you ever considered that the change in gravity might have affected some jabs?
When someone escapes Mario and Snake's jabs, they do so by sliding backwards along the ground. Their feet don't leave the ground for even a single frame. Gravity has nothing to do with it.
The first hitbox in Wolf's Jab 3 is low; that might be gravity-related. However, it's usually the second hitbox that misses, not the first. When the second one misses, it's because they've moved too far sideways, so again, that isn't related to gravity.