That you don't believe in any of the fables makes it impossible to to understand them. In the case of Adam and Eve, what if the fall of man was supposed to happen? If God knows all things from the beginning, it stands to reason God knew there would be a fall. He put an innocent couple in a garden setting with a malicious mastermind. In their innocent state, Adam and Eve would have been ignorant, knowing neither good nor evil. What would man have to gain from the fall? Everything. Going from a state where there is no growth, no progression, to a mortal environment. In mortality his very soul could be forged in the flames of adversity. But it was a decision man had to make. And through Christ, man gained the ability to become like God. (See I John 3:2) This he never could have achieved in a state of innocence. His body had no glory and he had no potential.
Next you mentioned Armageddon. But keep in mind that the JWs have a specialized interpretation of this great battle that correlates with no other Christian faith. In actual prophecy, Armageddon is simply a great battle between Muslim nations and Israel in the latter days. (See Ezekiel 38-39, Zechariah 12, 14, Revelation 11) On the verge of destruction, Jerusalem is saved when Jesus returns in power and glory to rule the world. It is not some event where fire falls from the sky and everyone but JWs die horrible deaths.
You're right about man degenerating at the end of the thousand years. When Satan is released at the end of that time, he will gather great numbers of people together in an attempt to wage one final battle, called after the first, Gog and Magog. But unlike the first, God will bring it to a quick end. Then will come the final judgment.
As with any religion, the Bible is open to many views and interpretations. The Jehovah's Witnesses, whatever their intentions, have one of the worst, most narrow theologies of any religion out there. It doesn't teach the love of God or his mercies. Everything is based on discipline, service, not in the form of relief efforts, but in conversion, and in consequences, of which there are many. Nothing is well thought out, so it's not really fair to judge the God of the Bible as seen through JW eyes.