Olympus OM-D EM-5 possibility for shallow depth of field?

I'm extremely close to buying into the OM-D and it's lenses as a camera to take travelling with me for a year.

The video quality seems amazing, and the image stabilisation seems great.

I'm wondering how easily a shallow depth of field is achieved with the OM-D EM-5 as compared to the Sony NEX 7 or the Fuji X-Pro1?

Does the smaller sensor make this a lot harder?

Thank you.