If I remember right, the 'medical background' thesis has been pretty effectively ruled out - the Whitechapel murders were more elementary butchery than they're generally seen as being.
The most likely suspect IMO was either Kosminsky or if not him then someone like him, purely because it fits in pretty well with what we know of serial killers today.
Abberline seems an extremely unlikely candidate... British intelligence organisations (incl. Special Branch) are renowned among academics for extreme levels of secrecy, withholding documents that are well over 100 years old. Obviously we can't really tell if there's a good reason for it, because we can't see the documents.