OK, I was pretty busy the whole week last week, and didn't get any chance to look into anything. But I cannot agree on this:
But all that aside, all changes that winecfg is doing are registry only
changes. IMHO Wine doesn't need yet another program to writes something into registry. There are already two: regedit and reg.
Yes, there are already regedit and reg to change registry, but they are not easy to use for regular users. Even a lot of Windows users don't know how to modify registry through regedit, not to mention those Linux users who have seldom, if ever, used Windows before.
I might be wrong on this, but according to my knowledge, most wine user just want to use it as "easy" as in Windows, and certainly not many Windows users mass with regedit that often -- that is why there is control panel.
I do think winecfg has its market, and to make it even better, I would like to combine it into the control panel.