This is an interesting concept but what exactly does OS4Emu emulate?
It does not really emulate anything, it is just an API wrapper for OS4 calls so you can run OS4 software in MorphOS natively. It includes AmigaInput, new DOS, Exec and Gfx calls and full P96 wrapper to CGX.
What's making my life a bit hard work at the moment, is the real heavy lifting stuff, Compositing , advanced reaction features,
What is missing is CompositeTags() call (for rotating and alpha blending) and I have planned to create Reaction to MUI wrapper. So far I have not invested time on it anymore.
band width limitation that make certain double buffering tecniques trivial on an NG machine but slow on Classic RTG.
WinUAE and NG Amigas are certainly fast enough to run any AmigaOS software.
Certainly OS3 can be made on par with OS4. It is just that nobody is investing time to improve OS3.