Since the OS is closed source the term "open Amiga" is an oxymoron.  BSD, Linux, Haiku and AROS are open.  You want an Open Amiga then release the source code and let us work with it.
+1
The Amiga OS as it stands is way behind the development curve of Linux and Windows, and while I certainly wouldn't say it's worthless, without large scale investment, allowing large scale development and publicity, it's going nowhere. Open sourcing is a way to get the large scale development and the publicity for "free".
If we could get it up to date, have it runnning QT, WxWidgets, Java, .Net, a posix layer (cygwin like) etc you're opening up to a whole new world of developers and compatibility with other more popular operating systems and architectures.
Then again we always have the open source Aros, MorphOS etc etc to eat away at whatever market share is left instead...