Well, actually, one could. Except that the result would be unbearably slow. The problem with the coldfires is that they only support 32-bit math, so every word-based or byte-based arithmetic instruction would require an emulator trap. And there are plenty of them, it's really a pretty common type of instruction on the Amiga.
Last I read was that some instructions were incompatible on the Coldfire that could not be trapped so the code basically has to be run under (JIT) emulation.