Oh man, totally, I made the move from Windows to OSX in 2011 and one of the main things I miss is the volume mixer.
Other things I wish OSX copied from windows:
- Turn off MBP's internal display while connected to an external display but keeping the lid open (not clamshell mode)
- Being able to control the sound level of my connected HDMI monitor (bootcamp windows lets me, but OSX shows a greyed out volume icon)
- Built-in window snapping, I had to buy BetterSnapTool on the app store to get it
That's pretty much is off the top of my head.