The primary goal should of course to be as simple as possible. And a 68020 can probarbly do everything that 030/040/060 can. Albeit slower.
My idea was if there were minor additions or bugs that one could have in mind when creating a softcore m68k.
Seems larger caches is one that could be implemented without wrecking compability too much. However any code should always have an switch to remain strictly compatible. Including bugs, as some software may rely on them.
A softcore 68020 is one stepping stone towards A1200,A3000,A4000,AGA etc..while there still exist original hardware to test any clones with.
