Just to understand their point of view, I think the BMW sound people would argue that they are using every tool at their disposal in order to provide the best integrated sound design and experience possible. Listening to the before/after sounds, they are "tweaking" the sound of the engine rather than replacing it. Sounds to me like the intake noise is louder, for instance.
However, I personally think when you do this, you are compromising engineering honesty, if I can make up such a term. You are masking the true nature of the machine you created, adjusting people's perception of it, in order to avoid doing something else. In this case, I think they wanted the car to be very quiet inside, so they put a lot of insulation. That damps out the road noise and such, but now you can't hear the engine. So some bright guy said, "Oh, we can just play the sound through the speakers! No one will notice or care because it will be perfectly mixed and synced with the engine." It might be well mixed and synced, but it is like fine furniture. You want to know your chair is well constructed with dowels and mortise and tenon joints rather than staples, even though the staples will probably do fine. That's why you wanted the ultimate driving machine, but now it's losing that identity.
The situation is kind of like how Honda started its downhill trend in the early 2000s. Making compromises in order to make a product for the broadest market, but slightly digging a hole for yourself in reputation and corporate philosophy. Over time, hole just gets bigger.