Plasma is amazing, from notification to applets.
If you don't like any of those, feel free to ignore them (you can disable plasma notifications and use Folder View as your desktop, tadan! you got your old desktop back).
No, you do not get your old desktop back!
(1) In the old desktop, if you pressed a letter key, an icon whose name starts with that letter would highlight, press the letter again and you'd get another icon.
[I don't care whether or not the following are specifically problems with Plasma or KDE4 generally, there are significant usability issues here.]
(2) In the old desktop, you could have different background on each desktop.
(3) In the old desktop you could bind a key to clear the desktop -- you didn't need to reach for an applet to do it.
(4) In KDE3 you could have the taskbar show only the applications present on that desktop. What is the point of the taskbar now?
(5) In KDE3 you could vertically stack small running application icons in the taskbar. Now running application icons look just like application launch icons.
Why isn't there a usability forum?