Look at the Eagles.I know the game has changed a lot since with all the passing, but IMO an offense that Washington with John Riggins and the Hogs could still work.
It's a huge offensive line that controls the line of scrimmage and allows a strong running back eat up 4, 5, 6 yards every time. It's ball control, clock eating offense that is based on physical domination of the line of scrimmage.
Why would this type of offense not work in today's NFL. It's boring ground and pound/grind it out but it just seems so basic and fundamentally sound.
Dominant offensive and defensive lines.