Should able-bodied actors play characters with disabilities? - yes, of course they should. In similar vein, if the director of The Theory Of Everything found a wheelchair-bound actor who could portray Stephen Hawking better that Eddie Redmayne did, they should go with the disabled actor.
It's argued that it's wrong to celebrate Eddie Redmayne "cripping up" - ridiculous. I've learnt a new PC term, 'cripping up'. These fairtrade coffee-sipping tosspots really do have too much time on their hands. It's very difficult to take The Guardian seriously.