If you have followed BMW, and not only, for the past several months, you might have noticed the general trend to drop big engines in favor of smaller ones with turbocharging.
I would say this is a normal progression considering the diminishing resources and the overall eco movement.

As far as performance is concerned, the result after downsizing is usually quite good, in most cases managing to get more power from the newer engines or at the very least match the level of the outgoing engines. But if there is one thing that is definitely lost, is the feel of the engine and the sound it produces.
This has already caused quite the stir among the more fanatic fans of BMW, albeit not quite a fierce one as the front-wheeled Bimmer, but still, there are those that feel the car maker has done wrong by the community. After all, the sound of the naturally aspired 5.0 liter V10 is quite unmistakable.
What these infuriated fans seem to forget is that the sound can be easily fixed with a nice application of a new exhaust system. For this job, there are plenty of aftermarket specialist happy to oblige, just like the next F13 BMW M6, which got a nice Castro GT race exhaust. Enjoy the sound.