Yes...but no. Sensors won't tell you if a turbine intake blade has been bent by a stone, or a panel warped so that the leading edge can catch air, or a landing gear tyre has "walked" around the rim from its set position. Or any of a large miscellany of other similar problems that the walk-around is supposed to pick up, any of which could potentially spell disaster, or at least a lengthy spell in the repair barn if not fixed early.