File Sharing With Versioning
Many projects have files that need to be shared among team members, who then modify those files. FogBugz can attach files to cases or wiki pages, but I'd like to see versioning of those files. You should be able to replace files with new versions, but still have access to older versions if need be. You should also be able to link to that file from other wiki pages, and have it always go to the most recent version (think soft links).
Fogbugz already integrates with multiple version control systems such as Sourcegear Vault and SVN. Isn't this idea redundant?