The following are blockers from product, design & technology point of view
- T148030: OOUI indexed dialogs (IndexLayout) / tabbed navigation (TabPanelLayout) is not accessible
- T180643: Altering radios doesn't make “Save” action available
- T180535: Don't duplicate fieldset elements in OOUI HTMLForm output
- Deactivated “Save” becomes active by just clicking anywhere in the surrounding fieldset (pre-existing issue from before OOUI-fication) – https://gerrit.wikimedia.org/r/423364
- T181691: [Pre-wmf.11] Special:Preferences asks for leave confirmation even when no changes were made (regression from OOUI v0.24.3)
- T181698: Headings of sections on "Gadgets" tab on Special:Preferences display escaped HTML after OOUI conversion
- T181733: MediaWiki:Gadgets-prefstext not wrapped in OOUI form in Special:Preferences
- T195986: FOUC in OOUIfied Special:Preferences
- T203825: Save not enabled when changing dropdown in OOUI special:preferences
- T203838: Lazy infuse OOUI widgets on Special:Preferences
- T192769: Special:Preferences: OOUI tabs cause a FOUC because the PHP side doesn't hack in their HTML, unlike the non-OOUI tabs
- T181770: Apex theme: Too much vertical space between form fields (Special:Preferences/MonoBook)
- Unbox the fieldsets on the page and work with whitespace instead.
- Layout of the read-only "basic information" section is poor (and the DOM is not good for screen readers).
- T181433: Widen / tweak the "Time zone" user preference to work in languages with longer labels
- T181430: Page Preview preference label newline causes odd display
- T181112: Sort skins by their ID and default position, not by their localised name
These are not blockers to switching to OOUI, but should get done at some point.
- T205866: Make save button more visible on Special:Preferences
- T34811: Direct link to a setting in Special:Preferences
- T198875: `id="mw-htmlform-opt-out"` occuring twice in DOM
- T194532: Special:Preferences: What's '(disabled)' supposed to mean in "E-mail me when a page on my watchlist is changed (disabled)"
- T194535: Special:Preferences-OOUI: distinguish titles and the values (declined)
- T204861: Reconsider keyboard user navigation hint exposure
- T203727: Restructure and improve 'Basic information' section
- T194533: Special:Preferences: rename the field titled "Signature" to "Signature/Nickname"
- T194524: Special:Preferences: Describe the empty text box ("Other timezone") with some placeholder text
- T194863: Clarify and align TabSelectWidget focus
- T203992: Random italicized text under Reading preferences section on Special: Preferences > Appearance tab
- T194525: Special:Preferences: Reduce the size of the <textarea>s shown for UsersMultiselectWidget when in non-JS mode
- T181844: Adjust UI elements for number entry on Preferences tabs for Recent Changes and Watchlist
- T181854: Better handling of 'instruction text' on Preferences tabs for Recent Changes and Watchlist
- T194531: Special:Preferences: For JS-requiring features, re-use the styling that Beta Features invented and show a red warning but only to non-JS users
- T198959: Beta Features SVG `img` elements miss `alt` attribute
- T199205: Beta Features `.mw-ui-feature-user-count` doesn't conform to WCAG level AA