Wouldn't it be easier to have a number (maybe in brackets) besides the review button at the top to show you how many items you can currently review? At the moment you have to click the review button to see if there are any items waiting, and there might not be. While it is not a big deal, I don't see why it would hurt to add this. Any ideas?
There is one already (actually it should be 2, one of them was removed due reasons, but it's being planned to be added back, or so I hope). There is also a feature request over MSE that may be interesting to you. But essentially, they are trying to bring those functions while not affecting the performance as Frank suggest.