navigation - How to explain to director that a multilevel dropdown menu isn't a good idea

My director and designer want to make a big drop-down menu on our site. Multilevel menu :

|     MENU 1     |     MENU 2     |     MENU 3     |     MENU 4     |
-----------------|----------------|----------------|----------------|
                 |  SUBMENU 2-1   | 
                 |  SUBMENU 2-2   |
                 |  SUBMENU 2-3 > |----------------|
                 |  SUBMENU 2-4   |  SUBMENU 2-3-1 |
                 |----------------|  SUBMENU 2-3-2 |
                                  |  SUBMENU 2-3-3 |
                                  |  SUBMENU 2-3-4 |
                                  |  SUBMENU 2-3-5 |

                                  |----------------|

I think it's a bad idea. I think it's very uncomfortable. Am I right? Is this really bad idea to do such a navigation menu on the website? (in 2011 ;) )

Answer

How about using a mega menu? http://www.useit.com/alertbox/mega-dropdown-menus.html