Probability is an abstract quantitative prediction of a specific events occurence at any given time, that is between 0% and 100%. Probability is always treated as dependent. It is the result of insufficient information about dependent variables in a system. Insufficient information can be due to many things, such as a lack of necessary equipment to observe certain causative agents, an incalculably large number of causative agents that lead to the prospective result, or 'uncertainty'.

1."An innate part of humanity is our capacity to change: over time as individuals, from generation to generation, following major historical/technological/scientific upheavals, etc. Part of these transitions involves the death of generational viewpoints, specifically through the death of individuals."

View points can die without the death of individuals. Your post, however, does no job at all of supporting your position.

2. "If I had the choice to live forever, I assume other people (or everyone) would be given this option as well. Us immortals would just get in the way of the future, probably develop some elitist statuses and might become cripplingly permanent connections to obsolete traditions and views. Think about it -- Thomas Jefferson was amazingly ahead of his time, but he still owned slaves."

Thomas Jefferson was ahead of his time because of moral and philosophical inquiry, and his ideas were pervasive because of the attention he gave to the moral and philosophical issues of his time. People figure things out during their lives and ideas have always had the habit of spreading like wildfire. To posit that a society, free from the promise of death, will stagnate is to underestimate our ability, as a species, to socially adapt and critically analyze. That's why we straight beast this planet in the first place.

3. "An inherent part of life is it's opposite: death. Without a thought for the unknown oblivion beyond some decades of existence on earth, what would our lives be worth? With an eternity of possibilities extending in front of us, wouldn't everything be reduced to triviality? If given the option to live forever, I'd decline, opting for some definable number of years filled with certain excitement and meaning, knowing they could end at any minute."

Arguments of tradition do not a valid rationale make. Sure, thermodynamics ensures our demise, making all life limited in duration. But that doesn't support the argument that it is better that way.

You will opt out because you, like most people, somehow believe that the meaning of life is lost if it is eternal. But you provide no reason to believe why, and there are many reasons to believe why not. You are more likely to accomplish all your goals, there is always a second chance if you get addicted to hard narcotics or go to prison for a crime you may not have commited, ect.

4."It's really cliche, but I also believe in paving the way for future generations and their ideas, allowing for the evolution of society rather than the stagnation that would most likely come from widespread immortality."

nope.