I think she's a great choice - she was fantastic in Broadchurch and also has experience in fighting aliens after appearing in Attack The Block. For a long time I was in two minds about a female Doctor ( Would it just be stunt casting? Is it too gimmicky for a mainstream audience? ) but I now believe it's an idea whose time has come and Whittaker is certainly a good enough actor to pull it off.
She had the following to say on her casting as Doctor Number 13:
"It feels completely overwhelming, as a feminist, as a woman, as an actor, as a human, as someone who wants to continually push themselves and challenge themselves, and not be boxed in by what you’re told you can and can’t be. It feels incredible... I want to tell the fans not to be scared by my gender. Because this is a really exciting time, and Doctor Who represents everything that’s exciting about change. The fans have lived through so many changes, and this is only a new, different one, not a fearful one."
And incoming showrunner Chris Chibnall added:
“After months of lists, conversations, auditions, recalls, and a lot of secret-keeping, we’re excited to welcome Jodie Whittaker as the Thirteenth Doctor. I always knew I wanted the Thirteenth Doctor to be a woman and we're thrilled to have secured our number one choice. Her audition for The Doctor simply blew us all away. Jodie is an in-demand, funny, inspiring, super-smart force of nature and will bring loads of wit, strength and warmth to the role. The Thirteenth Doctor is on her way.”
It's indeed an exciting time for Doctor Who and I can't wait to see the new Doctor in action...