the value of 0.1uF was selected to be tone neutral and allow the cap on the module to dictate the freq response for that module. It would seem that if a module does not have the tone you want AND the coupling cap between stage 1 and stage 2 is the tonal issue, then the mod belongs on the module.
Lets look at some calculations
If the Module has:
0.0022uF, effective coupling cap value is 0.00215uF
0.022uF, effective coupling cap value is 0.018uF
so a module with 0.022 takes about a 15% hit form the 0.1uF... from my experience that would be hardly discernible. but... if you are to change the cap, I'd go larger not smaller and allow the module to do it's thing.