To bad Avenue33,
I'm still looking for an Arduino GUI and finally I found "embedXcode". Even before I've had a chance to use it, it's gone.
I'm using PlatformIO with Visual Studio but, there's AFAIK no support for a graphical user interface on the Mac.
I understand your motives, but are we now in the hands of Bill? Though Linux could be our escape.
The alternative is of course to build and support a GUI for the Arduino IDE by the Arduino community, maybe we can even use your effort?