The only thing you 'need' to use is the Start Screen, but that should be a rarity since you should have the majority of your familiar programs down on the bar. Moreover, even when you need to use it, you use it the same way you do in 7. Just hit the windows key and type away!
My one complaint would be that the settings are a bit of a mess. There was clearly a rush to make things accessible from both the Desktop and Metro side of things, and as a result the settings can be kind of odd to find/navigate.
If it could really be disabled (and the disabling was supported by Microsoft instead of in spite of them) I'd agree with you, but it actually can't. Or at least Microsoft has gone obnoxiously far out of their way to ensure you will continually invoke it by accident, even if you tried to turn it off.
For example even after installing classic shell, random videos and photos still open the metro UI - full screen in all its glory. I also often end up falsely triggering the multitasking gesture (swipe from left=>right across trackpad). And the wifi-control panel has been turned into a brain damaged metro simpleton. And in 8.1, searching my start menu is going to return Bing results even if I was only looking for a file on my computer. My documents are going up to SkyDrive by default even though that might violate my privacy, cause me to break the law in certain industries that are regulated, cost me bandwidth or just plain be against my wishes.
If I had one word for this Windows release it would be "disrespectful". Because Microsoft has put all their own needs ahead of my own. In their selfish desire to promote their own products they have essentially become the bloatware that infected all their PCs and used to be the fault of the OEMs.