I didn't mind it in Akathen (no world has been more often misspelled than this in DW).
They clearly said that technology there was sound based, so the screwdriver didn't so much hold open a massive door but interacted with the mechanism behind it.
When he uses it as a scanner it irritates me more.
Interestingly enough the doctor USED to have a tricorder like device.
They should update that and then they have two toys to sell.
They don't even have to get technical about it. Just throw together some gizmo, call it timey-whimey dectector that goes DING! when there's stuff and be done with it.