Issue: Forward /wiki/name to /wiki/category:name if the former does not exist

The only way to achieve this automatically is if the link was generated using a specific BB-Code for the Category: prefix. In this case, the current behavior is to try both variations.

Otherwise if it is just a random incoming link, there is no way to guess the intended target prefix without greatly inflating the overhead. With a guess or even if a setting was used, you would cripple your ability to create both /wiki/name and /wiki/category:name, because category will basically just become an alias of "[No Prefix]". You should just use synonyms for the specific cases you need.

The solution is much easier: remove the 'category' prefix from each page.

If that is a viable solution for you, I will see about activating Mass Rename in the Mass Management Tools soon.

That would be great.