For example, the little "light" under applications that are running. From the pictures they don't look like a great idea. But once you actually use the build you find you are more productive. Same thing with the transparent menubar (499 it's actually fixed to work properly) but The idea is to not have the dock & the menubar staring you in the face, and to keep you focused on your application windows.
I know you say it's more productive, but to me (and as far as I can see) a lot of other people on these forums agree that the interface is no great leap over 10.4. It's nothing much after being baited with "Top Secret Features". About 4 new things were shown. To me it looks like the people at Apple were busy on the iPhone, forgot about Leopard and then threw together a seemingly updated GUI. It doesn't seem like they had productivity in mind, just change, to fool us into thinking some development happened. In short, they didn't innovate they just changed. Bit crappy considering how long we've now had to wait for Leopard.