Simply speaking, Unity is another visual representation to allow easy access to your installed programs. Compared to launching an application by using a keyboard shortcut, a menu entry, a docky/cairo/... dock icon or a graphical shortcut on the desktop, Unity uses a launchbar glued to left side of the screen plus a graphical menu where all applications are displayed as icons. Gone are the classic menus. Is this something to be afraid of? No, so technically speaking I see no reason to utter something negative about this way of representing an access method to launch applications.
So, if the change is not 'technical', maybe the 'problem' is to be found in the user/device interaction, about how users perceive input devices and how to make it easier to use those.
Currently we live in an environment where the WIMP principle reigns. It does so nearly three decades and it could be showing its age. Is the mouse as pointing device about to be replaced by fingers touching screen surfaces? This is nothing new. PDAs, mobile phones and iPad users are quite familiar with this way of interacting with their device and it works 'naturally' so to speak.
But older IT technology, typically computers - be it PC's, laptop or netbooks - still rely on a thirty year old concept. A screen, a keyboard and a mouse.
The new display interfaces will more and more include touchscreen capabilities.
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