It's mainstream light-hearted fun, it does what it sets out to do extremely well.
A lot of series that would be more philosophical or complex are not going to be easily accessed, and potentially have a barrier of entry, in that you have to more attentively engage with the text.
These kinds of series have cult followings, but it's nowhere near as accessible, but even they excel at what they set out to do. It's just not for everyone, which is a good thing. Not for the writers bank accounts but it is what it is.
It depends on the reader, most readers can consume One Piece, it's 5th grade level language, and it's easy to get the main key notes throughout the story, regardless of whatever can be speculated about.
If we look at Oda's intent, he doesn't like theory or speculation, he wants fans to just consume with their brain off and giggle at some silly moment he puts in. You can tell this is an idealised version of a young adult fantasy series because it's trying to capture youth in a bottle and keep it that way.
Every mainstream series will still have it's more hardcore fanbase, which is why we are on a forum. That will lead to contextual criticism (And I mean contextual, because the social aspect of the community reacting to the series) some valid, but others just come from a place of irritation because they want the series to be more like what they like, instead of just being One Piece.
And that usually happens when your taste changes over years, but trying to impose that onto a series that has always been set out to be a goofy shounen adventure, because Oda has wanted to write this final saga since the start, is illogical.
Reading weekly is not it, really it is a narrative that is intended to be one big story that you SHOULD be able to binge from start to finish.
Not something to craft theories about and criticise every chapter. If Oda could have it his way I think he'd want the series to be automatically done, so that people won't have to speculate and just consume from start to finish.
The Final Saga is the story he's always wanted to tell, if you seriously aren't enjoying reading it weekly, but you're still here. It tells me that you enjoy criticising the series more than reading it, which is not a good thing.
You can tell yourself all sorts of excuses and make it sound logical and reasonable, that what you're doing is fine, but is it really worth it?
Maybe it's just a way to direct frustration, but really you could be doing something else, but this is all you know now, so it's the laziest and easiest thing to do.
These One Piece Doomers who go and read a book or two, or maybe not even that and they just read Vagabond or something, and think they are at some elite level of literature that they can now trash a series they actively consume, are just straight up retarded.
Once you find something you can actively engage with and put time into and feel rewarded by it, you won't feel the need to behave that way, because you have an interesting thing worth pursuing.
These people are stuck in a void where, they are too lazy to move forward to find a replacement, feel it's too late to move back to the days where you just watched the anime for fun, so they just bash their head against a wall that's never going to change.