Taking a look at the Tiki Fact Sheet I read from the Ohloh rating that "Over the last twelve months, Tiki Wiki CMS Groupware has seen a substantial decrease in development activity. This could mean many things. It may be a warning sign that interest in this project is waning, or it may indicate a maturing code base that requires fewer fixes and changes."
Also the Forums don't seem to be very active. Over 1 million downloads (!!!) but were is everybody ?
The system has lots of good features, so what is holding people back ?
My guess is the current state of the Documentation and the lack of Themes. Any chance of finding talented Web graphics designers for a Theme Sprint ?
NOT a summer of code, but a "Summer of Themes".
In my opinion people are more attracted to visual than technical excellence. But of course, it's the technical excellence that will make them want to stay.
My guess is that more Themes would attract more users, and more users will get the Forums active and more people interested in cleaning up the Documentation.
A virtuous cycle.
Thus, my suggestion.