But then again what do you really need? Not long ago I thought 6 megapixels on an APS-C sensor were good enough for a perfect picture. Nowadays I think it ought to be 20+ megapixels on a full frame sensor. In the old days 5 frames per second was lightning fast, nowadays it has to be 8 frames per second or even more. Now we have Dynamic Range Optimization, picture styles, liveview ISO's up to 102.400 and so on.
But what makes a real good picture? Essentially it's only a few things: the right focus, exposure, composition and colour. And remember right focus isn't the same as everything in focus. Right focus is the best balance of sharp and unsharp parts in a photograph. It can even mean that there are no sharp elements at all. The overall unsharpness can give a picture a dreamy or mysterious atmosphere. The same holds for exposure, composition and colour. A picture full of lively colours can be boring, while a monochrome picture or a picture with a strong colourcast can be exciting.
Knowing this you can judge every new invention of manufacturers. Ask yourself with every new function: does it add to sharpness, exposure, colour or composition? If not, it's probably a non relevant function. Of course this judgement depends on your style of photography. For example: a sharp picture at a motorsports event is a little bit more demanding for AF, than the picture of a beautiful landscape.