These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Villain Decay: Or rather, ogre decay. Early on in the series, with one exception, the ogres were regularly portrayed as capable of feats of extraordinary strength. Later on though, they needed Gummi Berry juice to do anything beyond the limits of a human. And the weird side effects that the juice initially had on ogres was apparently forgotten.
Also, Lady Bane was malevolent and competent in her intial appearance, but later episodes featuring her have her fail just as badly as Igthorn due to Flanderization of her vanity issues.