the memory may be a problem here, but if its possible to get odyssey running on os4 "classic", then, considering os4 takes about 70mb to run itself and that the 68k executables need half the memory anyway in comparison to ppcm ones, it should be pretty easy to get it run on 128mb amiga, maybe less.
what concerns usability, as it was already said, if aros-owb works on an 060 equipped a4k albeit slow, odyssey should be much more responsive. this sounds as if it *could* be pretty usable.