By that logic he should have run up the engines and operated all of the engine and propellor controls through their full range, then shut down and inspected the engines and propellers.
Then removed all the inspection panels necessary to confirm that no control cable was fraying.
Then drained and replenished fuel to confirm that calculated and indicated equaled uploaded.
Then done an aircraft re-weigh to confirm that the loading and CofG data for the aircraft remained accurate.
What rubbish:-
Control cable inspection is a maintenance function, not part of a diligent walk-around.
Fuel logs and delivery dockets, properly managed, would assure the correct fuel was on board.
If there is a configuration change, equipment added etc etc, only then is a re-weigh is needed.
Engine controls etc would be as you want them as part of the start up procedure and, if not, you'd soon correct it before it's an issue. Their functionality check was on the previous flight assuming no intervening maintenance on them.
Trim tab position, however, is part of a thorough walk-round. Doesn't sound as though you check them properly.