I am aware with duplicate tool. It is always helpful to have symmeterical modeling in realtime. Seeing half of a model while modeling is a very annoyed, it is hard to determine if it looks right. What I suggested in my wish list to intergate symmeterical pointer with database system to memorize which polygon corners is made with symmeterical as a group. So that way I do not have to change symmeterical value everytime and may change by itself when mouse is on a specific polygon or corner. It is workable for any form of models especially disorted model. Now you see why I put some efforts to impress my wishlist for next version.