Usability issues are best categorized by types of users (developers, site admins and end users) and possibly by types of differing uses (public wiki), , group intranets, blogs, discussion boards, etc.) for tikiwiki.
Usability problems depend on the type of use. Those who are using tikiwiki as groupware or as a public wiki will have different issues than users who are using mainly the CMS features.
Tikiwiki needs to decide what it wants to be (this will likely be more than one thing!) and develop along branches/templates for specific uses.
Tikiwiki is a very powerful feature rich application. However, without a very knowledgeable administrator, these strengths can become weaknesses because end users are confused with all the options!
For most typical web users, the biggest usability barrier for tikiwiki is understanding the concept of wiki itself - mainly collaborative editing as opposed to blog or discussion board. These are barriers more psychological than technical, but the help/faq/documentation for the site should take special care to help people with this barrier.
End users should not be overwhelmed with choices. We should help site admins to pack away excess features and focus on core services provided by the site. For example, a newbie trying to edit this page will not recognize where the text editing area is, there are 6 different input fields 16 buttons and dozens of links.
The biggiest issue for new admins of tikiwiki as a large public wiki is the preponderance of features that are not to be used. The best solution for this is a redesigned admin interface that "buries" infrequently used features for this type of user and brings the wiki/article admin features to the front and center (hopefully with better documentation.
developing a good initial set of wiki pages that come with the install is key - include many pages from this documention as pages in a new install of tikiwiki.
if possible a configuration wizard should walk the admin through:
- choosing the set of features that is right for them
- developing an initial site map
- create the first set of menus
- create initial categories
- create groups of users
- apply permissions to categories
- introduce the layout options
- explain templates and customization
Key issues for a large public wiki include:
speed - how does tw perform when thousands of pages are created and dozens of users are editing at the same time?