If you feel there is an interesting feature missing in CKEditor, go to the development site: http://dev.ckeditor.com/ and file a ticket.
Please make sure you read the Bug Reporting Instructions and Ticket Specs articles beforehand in order to make it easier for the developers to examine the issue. It is also recommended to start from a search at the community forum to see whether the proposed functionality has not been implemented yet and offered as a plugin or code sample. You can also start a discussion to see whether the proposed feature could gain some interest from other community members.
When submitting a new ticket, feel free to attach your code suggestions or patches that can serve as a prototype for the requested feature.