So in the late 1800's Br Russell had to get everything spot on accurate and understand the entire bible straight away?
What exactly did Russell get right which is still believed today by JWs? They no longer believe that Jesus arrived in 1874, whether invisibly or not. His ideas on the creative day have been rejected after 1975 proved a letdown. The rapture did not happen on any date suggested or even implied by Russell. Even the 1914 date had to be amended because he thought Armageddon would come on October and JWs now claim they were predicting just a year and they're right because WW1 started in, erm, August. His whole views on every story of the bible having symbolic significance in the 19th and 20th centuries has just recently been abandoned. He thought the faithful and discreet slave was a single man, that's now been amended to a group. The pyramids of Giza no longer are the guides to understanding the bible. When was Studies in the Scriptures last in print from the WBTS anyway?
Arianism isn't new. The 144,000 idea is pretty unique but then there's more annointed now than there has been for decades, so something funky is going on with how God counts up to 144,000 if he was right. Non-belief in Hell? That's not unique either.
What are the things he got right which other religions don't also preach? It's a Trigger's broom of a religion. The 'truth' of the 1870s is very far removed from the 'truth' of 2015. Assuming there is a single truth to be discovered, if Russell was so wrong about so much, what guarantees are there that his successors aren't equally as wrong? Because they say so? 'Millions now living will never die'. Nope. They're dead. "Jesus evidently meant overlapping generations"? Really? How many generations overlapped in the 30 odd years between Jesus supposed words and Jerusalem's destruction?
Try telling that to the 18,479,257 Seventh Day Adventists who are in every land around the world.