OK, you are mostly right about the custom chips. However, emulation of custom chips is only necessary for programs that access hardware directly. If such a program only makes clean OS calls, then it will have no problems on a new machine.
Second, the MMU isn't an Atari custom chip. Most modern processors have an MMU, and many of the problems of the ACP are because the coldfire CPU does not normally contain an MMU.
However, the Coldfire 4e core processors (including the MCF5474 which is the one I would use from the family) have an MMU. This allows you to not only do real memory protection and virtual memory, dynamic libs, etc, but you can map all the hardware addresses of those custom chips to RAM and have any writes to that area trigger an exception - the OS then takes care of emulating the hardware access. The MMU is the trick to making it work, and I'm hoping the ACP team will realize this and not make an overly expensive design full of proprietary chips just for the sake of backwards compatibility with old games. There site does not acknowledge that the newer Coldfire chips have an MMU.
