The designers and management made a call to do what is best for the company and correct whatever mistakes they felt they have made in the past, time will tell if their decision is correct or not. You are focusing too much on the exterior styling of the car, yes given that it is the most dramatic and obvious change, the E-class has received some significant safety upgrades, so at least the 'management' got this right.
Of course they have to improve the fundamental tech and engineering of the car. That is par for the course with a facelift.
IMO a company that charges such a premium shouldn't be making these "mistakes" so often. The W204 interior makeover that had to be done was bad enough, now they're making it noticeable from the outside.
Whether the changes will finally get them back on track is a whole other question, who knows, but so far they leave little to be confident in (I wouldn't put my money on them until they prove otherwise).