I'm not 100% positive - this is off the top of my pointy little head - but probably
A. rejection of the trinity doctrine
B. rejection of the hell doctrine
Isn't it ironic that atheists feel the same way? LOL! I suppose you really cannot identify something solely on the basis of WHAT IT IS NOT, can you?
I don't know if Russellites originally had a belief in a paradise earth, by the way; weren't they all expecting to go to heaven? Maybe they thought everyone who wasn't them would be left on earth to suffer under their interminable rule. That fits..
As far as beliefs that are UNIQUE to Jehovah's Witnesses - what I like to call the "Dub Articles of Faith", described in THE WATCHTOWER, April 1, 1986, pages 30 & 31, "Questions From Readers" (my comments are in red italics. Note, by the way, that this is not a list of doctrines the WTS rejects, two of which are listed above.)
(...)
"Approved association with Jehovah's Witnesses requires accepting the entire range of the true teachings of the Bible, (as opposed to the FALSE teachings of the Bible, right?) including those Scriptural beliefs that are unique to Jehovah's Witnesses. What do such beliefs include?
So there may be others...
That the great issue before humankind is the rightfulness of Jehovah's sovereignty, which is why he has allowed wickedness so long. (Ezekiel 25:17)
Unchanged...
That Jesus Christ had a prehuman existence and is subordinate to his heavenly Father. (John 14:28)
Unchanged...
That there is a "faithful and discreet slave" upon earth today 'entrusted with all of Jesus' earthly interests,' which slave is associated with the Governing Body of Jehovah's Witnesses. (Matthew 24:45-47)
This has changed, hasn't it? First it was a man - Russell - then it became the WTS.
That 1914 marked the end of the Gentile Times and the establishment of the Kingdom of God in the heavens, as well as the time for Christ's foretold presence. (Luke 21:7-24; Revelation 11:15-12:10)
This was not one of Russell's original teachings, if I recall correctly. He taught that 1874 (or earlier) was the year of Christ's advent, and that 1914 would bring Armageddon.
That only 144,000 Christians will receive the heavenly reward. (Revelation 14:1, 3)
Yeah, I think that from the beginning they have interpreted this bit of Revelation as literal and the rest of Revelation as symbolic.
That Armageddon, referring to the battle of the great day of God the Almighty, is near. (Revelation 16:14, 16; 19:11-21)
Well of course. Armageddon is ALWAYS "just around the corner," isn't it?
That it will be followed by Christ's Millennial Reign, which will restore an earth-wide paradise.
I don't know if this is an "original" core belief or not... mea culpa
That the first to enjoy it will be the present "great crowd" of Jesus' "other sheep."-John 10:16; Revelation 7:9-17; 21:3, 4.
This is, I am pretty sure, a doctrine developed during Rutherford's reign as king of the earth. I mock...