(Yes, I really don't like doing it.)
I think all of these should be MediaWiki options but, for now, hacks/extensions will have to suffice.
- Extension:Multi-select Namespace Search (MSNS) - extend to Special:Allpages, Special:Prefixindex, Special:Recentchanges, Special:Contributions, and any other page that has namespace selection
- SpecialPages grouped into categories/English
- Display redirected page name in web browser URL location field instead of redirect's name
- Various special pages
- Lists to tables (sortable, easier to read, etc)
- Icons for text ("hist" and "diff", specifically) - Partially done ("hist" only--still need "Page history" too)
- Special:Logs - alphabetize select listbox for MediaWiki 1.9.3--done in 1.10.x?
- Special:Recentchanges, Special:Watchlist, and any other MediaWiki page - partially done but new logs don't sort correctly
- Go beyond # days and # edits dynamically without having to change preferences (and have a "More"/"Next # days"/"Forward"/whatever link at the bottom of the page for easier navigation).
- Sortable table - Done (example, more info)
- Show seconds
- Don't display "View (previous 50) (next 50) (20 | 50 | 100 | 250 | 500)." if there are less than 50 results (or whatever amount is chosen in Special:Preferences), to only show the actual number of results if they are less than that amount. - Done (hack)
- Show the total results--you know, basic search result output stuff... - Done (hack)
- Sortable table - Done (hack--example)
- Special:Suffixindex (see bugzilla:10808) - Doable with DPL (example); working on getting it into toolbox sidebar.
- Replace  "control" with customizable one that can use an image (like ) - Done (hack or extension); see Project:Support desk/Archive 9#MediaWiki:Editsection
- Disallow editing if page is being edited (edit queue? allow multiple editors only if editing different sections?); Extension:Ajax Show Editors can show editors at least but take it one step further...
- Sortable table with creation order and redirects columns
- Changable sort order (vertical vs. horizontal)
Hard to do anything there now since I'm banned...
- Cleanup Wikipedia:Template messages: group subpages, remove duplicate entries in "General" and "Cleanup", resection/interlink under template type (use categories as aid)
- This template should not have a forced white background (style="background: #fff;", white, #ffffff, etc) but should, instead, either inherit the existing background (style="background: inherit;") or, simply, not have any background specification at all. The same goes for every other template on Wikipedia.