Everyone in the media speculates about casting an ethnic minority, or a woman, but never a disabled person?
Imagine the thrill of a wheelchair battle between Davros and the Doctor!
He could also use the sonic screwdriver as some kind of supercharging joystick when he needs to roll out of a dangerous situation sharpish - like a surprise Chumbley or Mechanoid attack.
Maybe the chair could transform and give the Doctor exoskeletal legs so he can kick Cybermen in the bollocks, or avoid arrows from Raston Warrior Robots.
A blind Doctor could use his powers of echolocation by clicking his tongue every 10 seconds.
This would also transmute to a new found ability to speak to cetaceans and bats.