The visa wiaver program is not being ended. If you enter the US with a machine readable UK passport now, you will be able to continue to do so when you renew it. I believe that you will just renew your UK passport by post, in the usual way.
I understand that the UK machine readable passports now have a microchip embedded in them which initially will have your photo in electronic form (scanned from the photo you provide). It will have the capability of holding a fingerprint too if that is decided necessary in the future.
If you are just entering the US as a tourist, and you qualify for the Visa Waiver Program, you won't need to visit the US embassy in London to get a visa.
Andrew