Yes i agree with theymos.
Legendary already takes a very long time to get. I really do not think that ancient or veteran is really needed. The system is already pretty good and adding even more complexity can get confusing. I would say leave it as it is.
Legendary already takes several years to obtain. I feel like this is enough. Maybe if I someday start to see that there's some decently-sized subset of Legendary members who are "noticeably more veteran", then another rank would be appropriate.