I have an issue with the way AWB handles metadata. It's a relatively minor issue, but it's one I run into a lot since I regularly work with the uncategorized articles queue.
A lot of articles now get started in draftspace or user sandbox form, with category declarations that are disabled with leading colons so that the draft version isn't prematurely appearing in the category -- but people don't always know or remember that they're supposed to reenable the categories if and when the page actually gets moved into mainspace, which means that a significant proportion of the uncategorized articles queue consists of articles that do have coloned-out categories on them, to a much greater degree than was true three or four or five years ago.
The issue is that because AWB doesn't recognize a coloned-out category as a category declaration, it treats them as just more article text -- which means that if there's also a DEFAULTSORT tag in front of them, AWB automatically moves that down to the bottom of the page the same way it would have done if the defaultsort tag had been mistakenly placed somewhere in the middle of the real article body. Yet if an "uncategorized" page has such disabled categories on it already, then obviously the correct thing for me to do is undisable the categories instead of tagging the page as uncategorized -- but if I'm doing that, then because AWB unnecessarily moved the defaultsort tag I also have to manually cut that and repaste it back to where it actually was.
Obviously, AWB shouldn't be reprogrammed to automatically undisable coloned-out categories in all cases, since people may sometimes use AWB to process pages where the categories actually should be disabled. However, I would request that it at least be reprogrammed to recognize :Category: as being the same thing as Category: for the purposes of where the defaultsort tag should be placed.