Older ABS has a problem there, right. Modern ABS works very well on gravel or even wet gras. Most of the time one won't feel any difference while leisurely riding around. Even under bad circumstances most of the time you can do so much more with the front than with a locked rear... However, it IS nice to be able to lock the rear if you want to. Full time ABS front and deactivatable at the rear is the way to go, but if I had to decide all or nothing I'd take all ABS.
"Why not stay in disguise all the time? You know, look like everyone else."
"Because we shouldn't have to."