(not a wiki-style post as there are already two - but as the site just launched, only moderators/admins can edit wikiposts…)
LibreOffice will sometime in the future get a new UI - that is for sure as the tablet versions that sooner or later will have to exist need a different way of interacting (i.e. touch-interface), and I’m sure the whole UI-Layer will be revamped, making this possible and in turn easier to change the UI.
But then again it is of course a controversial topic, as some people don’t like change, especially don’t like MS-Ribbon interface, etc.
No matter what, it will still take time for this, so I definitely wouldn’t expect a different UI in 2012.
But when you mention Office 97 & colors (and not 2000 or the traditional menu structure vs always-adapting ribbons): If you’re using Linux, make sure that you’re using either GNOME/GTK or KDE/QT theme integration, otherwise you’ll indeed get a very old-school color scheme that adds to this impression
Also note that you can switch between different icon styles in the options, maybe that already makes it feel less “old” for you. (Tools|Options → LibreOffice → View)