User:Samsara

• Watchlists: Make hiding work correctly
• Admins: Make the display of protection templates automatic
• Watchlists: Remember last used namespace
• Admins: Button to quickly revert page creation vandalism

The first two are long-known flaws of MediaWiki. Both currently put vandals at a slight advantage and need to be fixed.

The last two are trivially easy to implement, but will make a difference to ease of use.

But the real headliner is would be could have been this one:

• Gadgets: Greatly overhaul media viewer (archived, with discussion ensuing)
  • Original proposal can be seen here

Another bug of note:

• Disabling pending changes removes visual highlighting and labelling of reverts and accepts