I've never run Fusion, but ImageFX runs fine for me, as does YAM, Voyager, IBrowse, Aladdin4D and FinalWriter. I've also seen people running Lightwave, TV Paint, Directory Opus...
And seriously, you can run it with the old Amiga icons from any version, even the glowicons.
My HD is the same HD from my old 1200. I didn't even format it, just installed MOS over AOS and it runs fantastic, runs almost all of my old apps perfectly. (Tornado3D doesn't work due to the dongle, but that was about it from my software) If you run Amithlon, you can copy anything you need from that, like the TCP stack. (I'm running my old MiamiDX from my 1200, for example, while one of my co-workers runs Genesis from 3.9) From my perspective, there is no difference between MorphOS and AmigaOS other than all of the headaches AmigaOS always gave me are now gone. MorphOS feels like all of the potential from my A1000 is now being realized.