Isn't a 10-minute impact player a game changer? Far more than most backs picked on the bench. Most back subs are only there to cover for injuries, not because they are likely to swing a game. In an era with increasing versatility generally amongst players keeping a bench spot for a back is seen as a waste (as it generally is if you have to pick a hooker there as well).
Its not so much the bench that people want to see changed as the ability of genuinely skilful players - i.e. halfbacks - to shine through. The argument is that they don't get space if tackles are slow and they are constantly facing relatively fresh big men who are mobile (bigger players now are far more mobile than they were).
I tend to think that what we're seeing now is part of an inevitable move in the sport towards athletes across the field, with reduced specialisation following as a result. A bit like the atom bomb, its impossible to 'uninvent' progress in sports science. I think its also important to remember that whilst some commentators and fans might not like it, a lot of coaches - particularly of course those who are winning under current rules - don't want to see things changed too much. In Australia that's a big deal because coaches are included in the rule-change process.
