>>1875462Wait, stop me if I'm wrong here, but I've always seen the lack of meaningful character development, plot, or depth in One Punch Man as a joke in it's self. Like, we all know if there was a character with limitless strength, like superman (I know he doesn't but you get what I mean), it would ruin any type of tension in a fight. Instead of trying to avoid or work around this issue, OPM plays it completely strait and is self-aware about this, and that's the joke. There's an underlying sense of nihilism in everything, and that nihilism is used for humour when it subverts your expectations for a simple reality.
Quick example, when they arrive the house of evolution, which had been hyped up for a while, instead of spending the episode fighting to reach the top (which it feels like they are going to do), they instead obliterate the whole thing, without even looking for the door, and do it power with to spare. It's funny, I mean, why wouldn't they just do that?
OPM is a fantastic satire, it's a show about strength where no one really gets stronger. It's a show about having goals where no one actually achieves their goal. Saitama gets a harder fight, but still doesn't get to try hard. Genos want's to find and destroy the cyborg that destroyed his village, but never does. Lord Boros wanted a fight that matched his power, thought he found it, but just before he died realized they were never matched to begin with.
Back to your post, One Punch Man and One Piece are hard to compare with standard means. Of course One Piece has more meaningful everything, OPM intentionally lacks direct meaning. Both are quality and popular for a reason, as
>>1875475 said it is really apples and oranges, but both are good, great even. OPM is exactly as you described, but if you look at it a bit further it's about a lot more.
>tldr: OPM is meta 
