The pads are small indeed but do their job fairly well. I never hat much problems with stopping the car and that one time I had a problem it was due to boiling brake fluid (this was due to the fact that I was disabusing my car over some French mountain roads, great ride though).
The rotors and pads on a C-class do their work very well.
If the pads did have the sensors stick in, you do not need to replace them...
with a minor 600+k