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.
All Animation Is Disney: The most prominent victim of this trope. He started with Disney before going independent, so it's only natural. And of course, it didn't help that he attempted a Disney-esque flavor with later films such as Thumbelina and Anastasia. But his films became Disney clones because that's what studio heads wanted. That happens when you aren't in creative control of your own movies, unfortunately.
Mis-blamed: SeeSequelitis, below. A lot of people blame Bluth for the bad quality of the sequels to his movies when (it cannot be emphasized enough) he had no involvement with any but one of them. This works the other way around for An American Tail: Fievel Goes West, probably the only sequel to a Bluth movie that people generally like, with some people praising the "good job" Bluth did on it.
He often suffers from Type 5 misblaming, the "Single Person Fallacy". And, as has been mentioned, many of the things that were wrong with his 90's films were more a result of Executive Meddling. And as was also mentioned on the main page, in many of his films he wasn't the actual creator per se, only the director of animation (leading to both misblaming and miscrediting).
True Art Is Angsty: His darker films of the eighties are much better received than his sillier works of the early nineties. However, this is justified in that the latter suffered from Executive Meddling, and thus couldn't reach the same level of potential as the former. Part of this meddling involved forcing Bluth to tone down his trademark darkness (and weirdness) in favor of a Lighter and Softer tone.
The Woobie: Several (if not all) of his characters. Also, you could argue that Bluth himself qualifies, considering how quickly his movies starting flopping after The Eighties, and how, to add insult to injury, many people mistake his films for Disney's work, anyway. Then again, he did leave Disney to begin with, so missing out on its re-invigoration could be seen as some sort of twisted karma; a kind of Hoist by His Own Petard where you actually pity the one being hoisted.
He also partly spurred Disney's renaissance by giving them a run for their money in The Eighties, sadly awakening a sleeping giant that he couldn't compete with financially (due to it coinciding with his parting ways with Steven Spielberg and intense Executive Meddling on all his films thereafter).
Even some Disney fans still can't help but feel sorry for Bluth, though it may help that many of them also enjoy some of Bluth's films. To them, Bluth was brave to try to make art of his own without the giant in that field, and it's therefore sad that Bluth didn't succeed.