There's actually a bit of interesting history here.
The iiMii version of Default Fe/Male was handmade by me the best as I could but originally, you could change the Default archetypes using the DefaultM.iimii and DefaultF.iimii files that are in your folder. (Latest version may have removed these two files, however) I wanted iiMii Make to be as customizable as possible that you could even get straight into editing with your own templates.
This was scrapped, however, simply because while developing the Android version of iiMii Maker, I didn't want users to fiddle with the files to customize the templates since it's looked down upon to Android users, compared to Windows users. I could re-enable it, though, in the next update for you!
Thanks for the feedback, by the way.