They now work on Yosemite.
AudioUnits with a custom Cocoa UI now display graphically
instead of reverting to the generic view
The Cocoa version of the generic view is now used when
needed...instead of the Carbon version.
The order of UI preference is Cocoa, Carbon, Generic,
unless force to Generic view user setting.
They now support realtime preview.
They also support dialog resizing as I found many that
scaled nicely (mostly Apple's).
Uses the new Effect format so now supports user and
factory presets.
NOTE: Be VERY critical when testing this as I've
never written Objective-C or Cocoa code
before!