I get your take on the story, except it wasn't the point of the story. Whether true or an allegory, the story was about God proving something to Satan, and that was that no matter what blessings Job had in life, he was still a good and faithful servant. It wasn't to convey to Job that he must undergo pain and suffering to appreciate the things God had given him.
As for paradise (Assuming it could exist), I think there is a distinction between lasting happiness and appreciation of happiness. It begs the question, can you have happiness without overcoming adversity. Which may be a question we could never know the answer to, since it has never happened in the course of civilization, or perhaps more to the point, how could you recognize happiness if you never had anything to compare it to. That being said, I can appreciate life without having to die first, so who knows.
I suppose to properly address the point here, one would have to first be able to agree on what paradise would be to humans, and then agree on what happiness might mean. To me, happiness doesn't just exist or not, it is in degrees, and perhaps paradise works the same way. Until we can put an end to wanting, we would only live in a partial paradise.