In order to fully replace the Navigation Pop-ups gadget, we need to get Hovercards to feature parity with it.
Below is the complete feature set of Navigation Popups. While feature parity is a general goal, some features are likely to be dropped
[] Mouseover on articles (including user pages):
[x] Preview the first part of the article text when mousing over a link to an article
[] Preview a section of the article
[] Preview old revisions (links with oldid query param)
[x] Preview the first image on each article
[] Preview selected page information: wikicode size, number of links, number of images, number of categories and time since last edit (age)
[] Identifies links as redirects, stubs and/or disambiguation pages
[] Action menu with one click access to
[] edit page
[] revision history / rss feed
[] most recent edit
[] edits by most recent contributor
[] changes since my edit,
[] move page
[] what links here
[] related changes
[] null edit or purge
[] wiki search, web search page title
[] action=render and action=raw
[] watch or unwatch
[] protect or unprotect
[] talk page
[] edit talk page
[] start new topic in talk page
[] Mouseover on image links:
[] Preview images
[] Preview file descriptions
[] Preview file links (usage on articles)
[] Tells you if the image is on Commons
[] Mouseover on user links:
[] One-click access to user page, user space, user talk, edit user talk, new section in user talk, e-mail user, contributions and contributions tree, user log, (for administrators) delete user, (for administrators) block user, edit counter (User Analysis Tool), block log
[] info on editcount, first edit, last edit, usergroups and indicator for blocked user
[] Mouseover on footnotes:
[] Preview contents of footnotes
[] Mouseover on categories
[] Preview category page
[] list first member pages of category
[] preview of category tree links
[] Preview diffs and access both revisions, in watchlist, history and related changes
[] Preview selected wikilinks when editing (use the mouse to select one wikilink in the editors textarea)
[] One-click revert of vandalism from history browser (see image)
[] Shortcut keys for actions (optional)
[] Fix links to bypass redirects and disambiguation pages (optional)
[] Should work on all Wikimedia wikis
[] popups for links in popups (including revisions/diffs in the revision history popup)
[] multiple skins and layout options
[] drag popups