I've always interpreted str or dex as part of the base roll, not a bonus to attack rolls, beecause of how the combat sections describe it. Also, because you can have a penalty.
And even for unarmed, there's a limited number where you make an attack someone in the process: disarm, trip, sunder, some grapple. Bullrush, overrun, dirty trick, drag, etc don't involve you attacking someone.