CreateWiki's UI is incredibly dated, and many things could be improved, leading me to believe it could benefit from a facelift (and therefore rewrite of all the frontend-related code).
One reoccurring issue that can be seen with the CreateWiki is the over-complication of the permissions system. While the fine-grained permission options CreateWiki offers are excellent and what we should be aiming to keep, they are not very user-friendly at the moment. In addition to this, the wiki 'type' value we ask users to set has no impact on these settings and sometimes does not reflect the permissions at all. Whether this is intended functionality or not is unclear.
Various other issues could be solved with, and many things improved with a well thought, loving redesign of one our key features.