Thanks for raising this again. It’ll be useful to get other such issues with Elephant & Castle NR together in one place.
One thing I am certain is that pink readers will never be sited in zone 1. A pink reader is designed to offer a cheaper fare and thus there is no compulsion to touch one. If you don’t and are overcharged then you won’t get a refund. Whilst I realise that a pink reader at Blackfriars would give you a cheaper fare at times, most people would be charged more. If TfL/SE/DfT decide that different fares are required then the via zone 1 option will become the default.
I for one will be very pleased if they ever put pink readers at Peckham Rye. I’ve a longstanding irritation that Sidcup and Woolwich line stations to places like Norwood Junction default to via zone 1 but Bexleyheath line stations default to avoiding zone 1 because of the direct Victoria services. Peckham Rye and Denmark Hill have always been mentioned on my route validators page as missing.