Problem: Oracle provide too much of tech boost if built by someone who already have Great Library. Prophet on Hagia Sophia is just to late and could be occasionally gained when you already cannot found.
Rationale: Oracle attracted lots of people and was one of the means of Greek cultural influence, therefore it's the best wonder for tourism bonus. Oracle was a place for some prophecies and therefore Great Prophet suits to this wonder more than current “almost free” Tech&Policy. Prophet on Oracle can really help found, on Hagia Sophia it’s always too late. Culture bomb is moved to Hagia Sophia to compensate Great Prophet. Current +25% religious feature now apply to all religious Units, not only missionary.
Spoiler Oracle :
Spoiler Hagia Sophia :
