Where do you get this? The Church is two witnesses? That's the first I've heard of that interpretation. I guess you could say Israel and the Church (Revelation does say they return from the dead... the new Israel?).
Normally, I've heard reference to the Law and the Prophets (or Moses and Elijah by name)... but that is usually taking a Revelation-fulfilled-by-Destruction of Jerusalem-approach. The Law lives again in Christ (fulfilled) and the Prophets are the Apostles and their successors. It's interesting to contemplate but we will know for sure in the occurrence.
As to the health of the Church... it is weakening in western culture, no doubt... but it is strengthening in Asia and Africa. What we need are bishops who will stand up for the Church with no hesitation or calculation. I think it was Archbishop Fulton Sheen who said that the call to be a bishop is a call to martyrdom... not many in the western world seem ready for sacrifice any more...
read the attributes of the two witnesses, it can only apply to the Church.