If it isn't used, but takes up space on a sheet, that's bad, imo. The less clutter for things that aren't used, the better. I'm not trying to convince anyone, btw. This thread asks what we want......I want simple, yet interesting (Nimble is very close).
You still are not answering my question though. How do you randomly generate your ability scores in a fashion that works if you are using just a -2/-1/0/+1/+2/+3 system? How do the other game systems you mention do it?
I am not saying I am against this, just that I don't see how you can implement it effectively without something else underpinning those modifiers.