Slightly tweaked??? The whole graphical user interface is REWRITTEN! The point and click commands may be the same, but the display will be completely different.
Rewritten from who's perspective? As a software developer, I can appreciate that a huge amount of work went into the interface.
But most people AREN'T software developers. They're going to look at it and see the same Start Menu, the same Recycle Bin, the same Programs List, and on, and on. Things have been moved around slightly, and (whee!) the windows can now have transparencies, but it's basically the same interface that Windows users are already familiar with. The fact that the screens are now rendered in the GPU rather than the CPU isn't going to mean squat to 90+% of the people who are actually going to be buying PC's.
So YES, the typical user is going to look at it and see the same old interface, with just a "few tweaks". There's NOTHING in the UI that would prompt someone to run out and buy a new computer.