That is disappointing, AOS would run on a 68000 and 512K ram, what more does AROS do to justify the faster cpu and 6M ram?
Aros was developed for and on X86 and never intended to be run on 20 years old hardware :-)
So it is not optimized for classic hardware whereas AmigaOS (classic) was and is tightly connected to the old hardware and parts of the OS were in the ROM to save memory. Try to run anything modern on A500, if you find anything you can show it to me because I would like to see it.
There is certainly still room for improvement in AROS 68k and the Kickstart Replacement but I do not believe that it will ever work on a 1 MB A500.