I disagree with the "see also" reasoning. The exact purpose of the "see also" is to point readers towards other pages which are highly relevant to the article at hand - a directory template or category, while useful, are simply to wide to work like this. "See Also" is especially useful for pointing towards "same design" enemies/items or "same theme/world" weapons, where a directory or category would be too arbitrary or impossible to name fairly.
However, the See Also sections need much higher policing - they should not focus on anything related to the article, but on things that are "different forms of the same basic thing", like I've done with Fire Ring, or Tailbunker.
For videos: I think we should only have one video per separate boss battle. So, no "Part 1" and Part 2". Also, they should be organized in the manner they are arranged on the page, and titled "Boss (#) (game acronym)" (The (#) being replaced with which ever iteration of the boss fight it is, so for Larxene, "Larxene 1 (KH:CoM)", etc.
I've also noticed that the ogg files we have can make the browser's crash - this might be just mine, though.
I think galleries should include art or sprites of the article subject, when they are different from the presented image, and when they cannot be placed in the infobox (like the Soul Eater for KH1). So, we could have the different forms of Sora, but we don't need an official art or GBA version of each Heartless. Screenshots should be incorporated into the narrative instead.
I think trivia should only include stuff like "this is the only one" (but not if it includes any exceptions - so, no "This is the only one, if you exclude x") OR stuff like the Roxas AirWalk shoes. Anything that is relevant to character design or narrative should be incorporated into the main article.
I think the categorization needs to be such that 1) The same article is not placed into both a category and its parent category, 2) Categories are nested wherever possible (so Heartless includes only the two subcategories), and 3) An article for a group is not placed into a category unless all of it fits - so, Organization XIII would not be placed in "Characters who use Flowers", for example. Similarly, "List of Keyblade wielders" would not go in "Original characters" or "Disney characters", because of Mickey. The game-based character categories should be inclusive, though, not exclusive.
I agree with DTN on the one-linking - only the first instance. However, because of the tabbed nature of our infoboxes, I don't think they should count, since they are not always visible, and I think section-specific links, like "Traverse Town#First District" should count as links to "First District", rather than to "Traverse Town".