A brief comment based on my own experience:
The W221 was the S-Class that I liked the least:
the interior and exterior design
the cheap plastic in the interior
the poor quality
and above all: you couldn't drive the car fast. Above 160 km/h, the car became unstable and couldn't hold its lane. That was completely terrifying.
What a revelation the W222 was. I thought that only small steps forward in development were possible – but I was completely wrong.
Design, quality, appearance, feel, operation, high-speed driving – everything was superb and on a new as well as absolutely outstanding level
It was the kind of leap in innovation that I had only experienced before from the W116 to the W126. And I believed that something like that would never happen again (except for the W140 I drove all S-classes since the W116).
The W223, on the other hand, was a real disappointment: feel and material appearance, (partially built-in) quality defects, and, of course, the all-touch operation, wich is too distracting especially at high speeds. All that made me switch to the BMW G70 (I am so satisfied that, for me, the BMW is by far the better choice).