I think it is a matter of personal choice. I have never tried the melody maker tuning, though I can see its advantages. I did consider the melody maker scale but decided that the Paddy Richter tuning would suit me better and I feel I made the right choice.

Anthony Dannecker does make harmonicas in Richter Tuning. He refers to them as "Major" which is really the standard tuning. I have a low D from Anthony Dannecker in standard (ie Richter) tuning.