I've not upgraded my KDE to 3.3 yet, but I've heard that the easiest way to do that in SuSE is through apt-get:
About the menu disappearing, as far as I know, KDE won't display empty submenus. For example ">> Aplications >> Games >>", if you Games submenu is empty, it won't be showed in the menu...
Gnome is a very nice Desktop. Unfortunately, it "feels" pretty broken in SuSE, not very polished and with a messy menu. That's because SuSE has been a KDE-driven distro for a long time. Things might change in the future though... since Novell now owns SuSE and Ximian Desktop... But try it anyway, you might like it, I do...
Take a look into SuSE forums or IRC. If that's a bug, somebody else is also having that problem and most likely, SuSE will fix it soon.