You're at odds with most of the motoring press then Fuzzer!!! From my experience, they generally seem to knock the C but this time around they loved the interior.
I thought it was better personally, the instruments look more modern as does the new climate unit. I also disliked the old 'plastic hole' underneath the Audio 10 which has now been subsumed by the new Audio 20. The old hole just didn't look right, unless you had satnav to fill it!
I'm with Fuzzer. Those chrome instruments look a bit tacky to me and I really dont like the climate control unit, too cluttered, fussy and too much chrome. Keep it clean and simple!
When you say it feels cheap .... just precisely where did you put your hands ?
Mercedes does offer several trim options. You could not have been sitting in a Designo C55. That certainly doesnt feel cheap.
In any event I should recommend a BMW 3 Series. (I have never seen a better reason to buy a Mercedes.) That 3-series fudge ball has never been larger and yet the engines seem to remain the same.