Make properties changes affect all selection instead of active object only

Currently when you change a propertie it affects only the active object.
If you want to affect all selection you need to use Alt on a field ( Alt + Drag or Ctrl + Alt + mousewheel or keep Alt pushed when direct editing a value) This was added in 2.76 if I remember correctly (I was so happy ! Finally stopped using tiny python script to modify properties!)
It's a super usefull feature yet unknown by most users.

My proposal is to invert this :
Any modification on properties would affect all the selection and Alt key allow to affect active object only. I think that it's the expected behaviour for most users.

I dont' know if it's currently possible since Alt doesn't work for all properties.