Value editors can already be extended as per http://cwiki.apache.org/confluence/display/DIRxSTUDIO/Value+Editor+Extension+Point
Although there is an old old task DIRSTUDIO-22 for improving usability with common entities (such as groupOfNames), a simpler first step improvement would be to create an editor for the common "member" attribute. It should be capable of resolving the DN value to the CN of the related record. A brief discussion was had here: http://markmail.org/message/vi3uyjkennzdu727
This improvement would make a huge difference to the ease of managing LDAP directories which use groupOfNames extensively.