Usability consistency is needed in the wordPress community. Plugins and themes should both be as usable as wordpress is. The best way to make things usable is to do REAL usability testing with REAL people. Don't worry about what's supposed to be usable. See what ACTUALLY works.
Code is poetry. So should be your user’s experience.
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Help Us Help WordPress | Smashing WordPress
Learn how to improve the WordPress user experience with some practical usability wisdom.