I actually like the changes in characterization, I think they work well. There are also many technical aspects that I think are remarkable in the composition and sometimes the choreography.

It looks incredibly silly, and if it were to come out on its own (in a world where one piece didn't already exist), people would be baffled about wtf they were watching.

All of this is true, but none of it furthers your point. I love how silly it is, that's legitimately a core part of the appeal to me. There are pluses and minuses on both sides, but I honestly like the adaptation more than the part of the source material that it adapts (especially the oft-disparaged anime). I miss the better-developed Buggy crew and such, for instance, and I think the Gum-Gum powers really suffer from the mediocre CG rendering, but the ridiculousness of Garp on his dog-mast ship throwing a cannonball like a shotput is wonderful, and Luffy taking the impact looks surprisingly good.

More things should look weird and silly, and if the artists behind this adaptation made an original project, I'd be excited to watch it.