I would guess one or both of two interpretations:
Heaven is impossible.
Happiness requires contrast.
Of course, some speculate that heaven is a joining with god, but in that scenario your current self is still dead, gone forever, so you really REALLY need to be okay with the concept of surrendering yourself to your god, because the best terms it is offering are "I will completely reformat everything you have and everything you are to suit my whims", which sound to me about as bad as they come... It is interesting to note that the idea of the world being a god's imagination is compatible with that. The world exists to entertain some extraworldly entity and it retains memories of you, but you still completely cease to exist...
If happiness really does require contrast, which is by no means certain, then it is a perfectly predictable scenario based upon the nature of humans, which is supposedly dictated by an intelligent creator, which presumably created the world, and its occupants, with the intention that they would suffer no matter what they did. No matter how ignorant it chose to be about the future, nor how much freedom it chose to give humans, such a creator specifically chose to make them suffer...
In either scenario, heaven is not much of a reward...
You've gone a long way out of your way to try to avoid the simple fact that the first assumption, "The proof is along the lines of, something happens that results in someone being less than satisfied. At that point there is a flaw in the world, if one assumes that a 'god' exists, then its existence would need to be justifiable in the presence of such a flaw," is opinion.
Everything needs to be justified with everything else, if its existence cannot be justified then it cannot exist. Pizza can be justified with crime because producing odours and going soggy are not actions that typically impede criminal activity. Police can be justified with crime because they lack the resources to completely stifle it. Christian style gods can be justified with respect to crime because... They lack the ability to stop it? They choose to allow it? They choose to let people do whatever they want, but chose to create them with criminal inclinations in a world where crime is sometimes necessary for life, morality, and the perpetuation of their religion? Or did these intelligent creators just choose to mentally cripple their children so that they couldn't understand the divine workings? If I saw a parent repeatedly dropping their child on its head so that it would be satisfied in the endlessly repetitive manual labour it would inevitably find in its only career options, then I would expect any good christians in the vicinity to seek to stop them...
Obviously, Lucifer does not consider God to be perfect, but if God is pleased with the result it hardly matters.
It matters to Lucifer, it matters to humans who are stuck in the middle of it, it matters to everyone but this god, am I supposed to respect something that chooses to be so ignorant of others? I would sooner face it in a hopeless conflict then hopelessly try to enjoy its company...
Disliking the state of the universe does not even begin to address the existence of God.
It does if the state of the world was created by a god and that god takes issue with things that people dislike. Of course, if the god wants people to endure things they dislike, for its amusement or something, then it doesn't so much address the fact of its existence but just the nature of its existence...
You say people cannot come to an agreement on terms, but again this is not true. Rather, you and folks like you refuse to accept agreed upon terms because doing so results in settling the matter rather amicably. Atheists are currently at great pains to come to a point where religion can be banned entirely, so assertions like this followed by a lot of noise meant to obfuscate the obvious flow like water.
I don't want it banned, in fact the thought of completely banning anything is somewhat distressing, but I am very worried about a world in which religion is valued more than personal integrity...
Facts. Let's deal in facts. You cannot rely on logic if what you are dealing with is personal opinion. What is or is not "perfect" is a matter of opinion.
To me, perfection means to adhere exactly to something's nature. Perfect water would be pure water, it may not be nutritious enough to be healthy as an exclusive drinking source, but it is, in a clear sense, perfect. Of course, if you redefine water to a conductive medium, then you need to have some salt in it, if you redefine it to "the stuff that comes out of the tap" then it is perfect until you do something to it... But whatever the case, perfection is easily determined and once defined ceases to have any correlation to opinion. Dissatisfaction is a flaw in fulfilment, which is often cited as a value to religion, there is absolutely no opinion necessary to sustain that...
Logic can easily be applied to opinion, as opinions are formed by, and therefore dependant upon entities with logical natures. Not to mention the ability of logic to be used by the unscrupulous to manipulate the very much logical processes that form opinions...
It seems odd that you quoted my entire post, when you only responded to the first paragraph...