It takes intuition to make a good product. Bill doesn't have that, or there would already be a profitable product on the market.
If OS5 has a decent core, but uses the same braindead shells and file requesters as Windows, OS3, and just about everything else, that's a pretty good indication that the OS is destined for failure.
Apple couldn't write their own OS (Copland), so they dumped that project and built an interface on someone else's OS. Look where it got them. If Bill is spewing the same BS that OS5 will be better than OSX, chances are Amiga is still focusing on the core, rather than that new shell and file requester.
I don't doubt that OS5 will be released eventually. It just won't be worth using.