this is what i find when crafting at least it appears to be true for all the new recipes i synth, it may sound stupid but please try it out before ruling it out

magic craftmanship - higher stat gives a higher quality gain with a successful synth.
craftmanship - higher stat gives more progress gain with a successful synth.
control - higher stat gives better chance of a successful synth.

I still dont believe the whole one stat for one synth sort of deal, i know people who stack purely craftmanship for hq nuggets whilst others stack mag craftmanship n both believe they have the best set up lol.