Thank you for taking the time to reply so thoroughly! Haha XD
I was actually going to mention reincarnation in my 'little' rant but I thought I'd spare the length XD I was going to say that in order to get out of this maddening 'balancing' trap you'd either have to give up the idea of a 'balance' or you need to say that a person has multiple lifetimes through which Karma can do its job. However, multiple lifetime would, inevitably, multiply the problems that start on the individual scale, not minimise them. Yin and Yang thinking, in itself, requires us to not see ourselves as meaningless in the cosmic plan but central, since changes which happen within will multiply and ripple outwards. A crack in the foundation will only grow, regardless of whether you refurbish the building above it, or rebuild it several times over. As long as the foundation is cracked, it will continue to get worse. So, giving a flawed individual sever lifetimes does not minimise the problem but only aggravates and exaggerates it.
As for subjectivity, I completely agree! We cannot see the balance ourselves, which is exactly the question of how could we decide what to do in any given situation? Should we do anything at all? If we do not know the current position of the balance scale then we cannot possibly know the consequences of our actions. We could be bringing balance, or we could be destroying it.
For example, suppose I am rich and I pass a homeless beggar on the street. I happen to be able to give this person enough cash so he could rent a proper home for a while and fix his life. This could go any number of ways, but to simplify, for the sake of conversation, two things could possibly happen: He could actually fix his life, become rich, then remember me and repay me back in full one day. Or, if the universe sees my action as a destruction of the cosmic balance (since this person was born a beggar due to his bad Karma from a previous life, lets say), so, in order to restore this, another beggar sees us, becomes jealous, stabs him and steals all the money. How could I possibly decide what to do in this situation? Should I be charitable, or should I pass him by? My charity, after all, could lead to losses on both sides.
This is why I see the idea of balance as very fickle and emotionally unsatisfying, most of the time. Usually, it's presented as some sort of divine justice, but such a thing does not exist in a Yin and Yang universe seeking balance, where the best possible lifestyle is to retreat to solitude and meditate so that you have as small an impact on the world as possible.
Thank you, again, for taking the time to discuss this with me! ^_^