The balance in the Force is not the "absolute good" from the Gray Jedi perspective, it simply exists, and it defines the state of our lives. It is the Jedi Order and the Sith Order who believe that restoring balance to the Force from their own perspectives is doing an absolute good.
The role of the Gray Jedi Knight is to keep to the balance between the Light and the Dark Side, ultimately succumbing to neither. We exist to help keep this dynamic balance in the Force flowing because we understand that life is at its most fruitful, and at its best when there is Light and there is Darkness -- for all creatures of the universe. We don't recognise an ultimate good on either side of the Jedi-Sith, Light and Dark Side war.
This is an open discussion, and I have no reason to challenge your beliefs. As I've said earlier, I believe this perspective makes you a proper Jedi of the Order -- the belief that good will triumph over evil, and that evil exists.
The topic's question is "What does it mean to be a great Jedi?", not why would one be a Gray Jedi.
Please note that this is not a topic about me, personally, altough I do believe I've explained in detail my personal point of view, and attraction to the Gray Jedi way.
There is no point in trying to discredit me, @@Boothand, @@Ping, as what I've said I've based on direct evidence and my personal interpretation from official dialogues in the Star Wars sources we have about Gray Jedi. You are free to have your own point of views on this topic, but please don't claim that my own are invalid. It would be nice if you could back up your views with source evidence as well (so I'm not the only one)...
I would like it if we drifted the topic's theme away from a focus on Gray Jedi, and back to the general perspective people have on what it means to be a Jedi.
I will answer your questions as they pertain to my personal understanding of the Gray Jedi way:
1. This is right. Every individual is responsible for their own action, and the effects of their own actions (which are neither "good" nor "bad" in the ultimate sense, but a mixture of both).
2. Every Jedi feels the flow of the Force, and every Gray Jedi is aware of the balance between the Dark and the Light Side. What they do with that knowledge is at their own discretion.
3. None of your efforts will make the scale topple over. The state of the scale affects your life as it pertains to now, and your future. Whether a Gray Jedi chooses to help change the current state, or is content to hide away and exclude themselves from the current state of the galaxy, nature will not crumble, and things will balance themselves out eventually. The only thing that is truly affected by our actions are our own lives. Good will never triumph over evil, and evil will never triumph over good, truly. They are essential to humanity, and unseparably connected to one another.
4. If the proper Jedi way defines the state of the galaxy, I believe people will suffer just as much as if the Sith way were defining the state, yes. We haven't seen too many examples of this in Star Wars so far -- the focus has been on evil (from the Jedi Order's perspective) coming out triumphant, and stopping it from doing so. However, you can see glimpses of the traditional Jedi ways crumbling when faced with taking a side and getting involved in the happenings of the Clone Wars. The Jedi Council's unwillingness to accept that where there is Light there is Darkness in their actions, and in a person is what makes ultimately the Order weaken and crumble from the inside with the fall of the Chosen One, and their fight against the Dark Side cause suffering to countless Separatist civilians.
5. I was not talking in absolutes -- I'm nor Jedi, nor Sith! A period of peace is valuable often, but conflict (not necessarily the most extreme form of it, war) is just as valuable.
6. I have never said that Gray Jedi are necessary for anything. No individual living creature is necessary to the Force, but we are all a part of it. I was merely explaining what a Gray Jedi may choose to do to try and influence the state of the galaxy, at their discretion, because you've asked me, specifically.
7. Making an impact on another culture as an outsider, without knowing or respecting that culture is wrong, yes. I do believe this. Do not do unto others what you would not have done to you. And if you do so, do not expect that it will not come back to bite you in the ass.
You don't know this. Just because it hasn't happened in a drastic way so far doesn't mean it never will... If the Sith Order and the Dark Side users were vanquished, it might very well happen. We recognise that a galaxy dominated by the Sith would be out of balance, but why do most of us not see the same for the Jedi? Is their Code any less extreme in its definition? Are their people any less flawed? These are questions I would put to you as a Gray Jedi.
Also, not every Jedi of the Order would agree with your perspective here. Some believe that it is not the Code that is the problem, but the flawed people who interpret it.
I believe it can. It can very much slow down human progress, and make us forget the values of conflict. Peace is not desirable in a world where everything is stale, and there is very little progress. Where people grow bored of not being challenged. You grow weakest when you are at constant peace. It is through conflict that you gain abilities that better your chance for survival, and give you values that define your sense of self.