Please forgive. My effort at trying to be succint as made me vague. I am sorry.
The point, "One's heresy is another's doctrine" rings the bell of "One man's terrorist is another man's freedom fighter." It sounds like trying to please the other point of view while reinforcing your own. Doesnt really get to the point of anything except maybe stalling. (Sorry, philosophy is one of my minors. That is why I saw your quote that way.)
Concluding the betterness of humans in that state rest, perhaps over-relied maybe, on that when God created everything, including Adam and Eve, God said it was good.
Gen. 1:31
And God saw every thing that he had made, and, behold, it was very agood. And the evening and the morning were the sixth day. KJV (scriptures.lds.org)
Gen. 1:33
And I, God, saw everything that I had made, and behold, all things which I had made were very good. And the evening and the morning were the sixth day. IV(JST) (
http://www.centerplace.org/hs/iv/default.htm)
And you are correct, if Adam and Eve had not fallen, there would be no need for the atonement.
I am not sure I understand that last question in the paragraph. Sorry.
The Book of Mormon casts the fall in slightly different terms than you just did. In verse 25, it says
Adam fell that men might be; and men are, that they might have joy. 2 Nephi 2:25
Am I assuming too much on a Book of Mormon scripture or a Bible scripture? I will try to avoid making such assumptions then.
I think we misunderstand each other on the dead weight issue. By Christ's atonement, mankind is redeemed and is in right standing with God. Or as Athansius would put it, "God became man, so that man could become god."
I hope that clarifies what I have thus said.