6. He Isn't Over-Reliant On Technology
The latest Doctors have really depended on the sonic screwdriver to get them out of jams. You know this is a problem when writers have to create deadlock seals just so the Doctor can't run through every locked door he comes across. He also has a habit of using his screwdriver to hack into highly secure computer systems, scan the area around him and do instant comprehensive scans of things he finds. There isn't even a screen on it, so what does he look at? He can't run down a corridor without waving a sonic screwdriver around. The Ninth Doctor gets his hands a bit more dirty than the others and uses the sonic screwdriver like his older lives, more to set off or detect nearby things. This is balanced out later by Captain Jack Harkness being the one who carries around the sonic blasters and builds the weapons at Satellite Five. Also, while he does use the sonic screwdriver to get by, the things he's sonic-ing typically put up some resistance which I'll take over Matt Smith's whizzing around every time.