hey fabp ,
if u could get this implemented it would truly make my year as i use all 4 Arturia synths heavily.
The reason , well with the current tuning limitations , i can only compose using a very limited number of conventional musical scales. If this limitation was removed , i (and evryone else) could use more esoteric and diverse scales e.g chromatic just 4ths or the 7 just minor diatonic scale , plus it would let people make up their own scales to suite their tastes.
There is just such an enormous musical world out there but composers are very limited unless softsynths support full microtonal retuning.