Hello Troubled,
Hope that you are well.
There are a variety of doctrines that hold the WTS apart from the mainstream of Christianity. Fifty years ago there were many more. Gradually as time goes on the WTS 'adjusts' its teachings. They claim that this is under the oversight of Christ.
These altered doctrines move the teachings of the WTS closer and closer to the mainstream of Christianity as each decade passes. Though exclusive claim is made on these ‘new’ understandings, they are in basic fact what the mainstream churches have taught for hundreds of years. To illustrate, the ‘flash of light’ that led to a new understanding of the ‘sheep and goats’ judgment which the WTS now teaches did not start in 1919 but happens at Armageddon. Another is the adjusted ‘generation’ understanding.
There remain a number of doctrines that the WTS are proud to proclaim that they have an exclusive understanding of. These teachings have often been elevated in importance to the detriment of the simple message of Christ as preached in his many homilies collected together and described as the ‘Sermon on the Mount’.
Your search for Truth would be well directed in examining each of the ‘exclusive’ teachings of the WTS in depth. You have focused on one, the ‘door to door’ work which the WTS says is God ordained. It clearly is not, but NWT scripture was bent to suit this claim.
Others to carefully research are :
1) Use of Gods name - why was the name Jehovah’s Witnesses really chosen?
2) Why is this name effectively non-existent in early Christian texts?
3) The Blood issue - when and why did this become an issue.
4) The ‘parousia’ - what does it really mean?
5) Exclusivity of one religion - Matthew 25 will help view the reality of this issue.
6) Does the WTS have scriptural basis for its methods of disciplining its adherents. Have they gone beyond scripture, if so why?
Other posters will add to this list I am sure but as you research and find answers, hold on to your hat!
I personally have no doubt that most of the list above will not be part of the teachings of JW’s in ten years time, with the exception perhaps of the use of the name Jehovah, which is as good a brand name as any for a religion intent on forcing a separation between itself and the rest of humanity. Their teachings will then resemble to a great degree what the mainstream churches preach today and taught yesterday, and then perhaps the whole notion of ‘light flashing up’ with new understanding will be laid to rest in the Hall of Theological Embarrassments where it belongs.
My best regards to you in your search for truth - HS