Let's face it--everyone hates the status quo. People equate the phrase with stagnation, boredom, lifelessness, and a flat unchanging nothing. Everyone insists that stories should "kick against the status quo" (especially in comics, where there's practically a jihad going on between people who hate it and people who love it.) And nobody seems to understand what the damn thing is. So here's a quick explanation of what a status quo is, and why you should love it.
Any series (not just comics series, but TV, movie, video game, manga, what have you--any setting that is designed to tell multiple stories based around a character or group of characters) must have a status quo. That status quo is the baseline setting and context for the series, and it functions as a generator of stories. That status quo can be anything from "a group of people in the workplace that don't get along very well" to "a man with a magic box that lets him go anywhere in space and time" to "a mystery writer who actually solves mysteries" to "a group of mutant superheroes that help a world that fears and hates them." (Obviously, these are just thumbnail descriptions: A real "status quo" for a series involves descriptions of each character, what makes them tick, the world they operate in, their relationships to each other, et cetera, et cetera, et cetera.)
That phrase, "a generator of stories," is an important one. It means that there are stories you can tell about these people that come out of the setting and context you establish, stories that are interesting in and of themselves. Obviously, not all status quos are created equal. There are a lot more interesting stories you can tell about "a man with a magic box that lets him go anywhere in space and time" than you can about "a group of people in the workplace that don't get along very well", which is why 'Doctor Who' is still going after 43 years and even a great workplace sitcom like 'NewsRadio' only lasted five. Not all settings and contexts have the same number of interesting stories to tell about them; some have very few.
Now, this is where the comics community has bandied about terms like "real change vs. the illusion of change". There are two factions in comics that each have very strong views about making major changes to a comic book; the "real change" people insist that change is an important, naturalistic element of story-telling, and that by forcing the characters to conform to an unchanging model, they've made them stagnant and lifeless; the "illusion of change" people insist that when you make major changes to a character, you're losing as much as you gain, and all too often you can lose the thing that makes the character special.
But here's where our above definition of "status quo" comes in, because it not only explains away the seeming contradiction between the two, but also explains the existence of the third type of story that neither side seems to acknowledge: The story that is exciting without having either change or the illusion thereof. That type of story is the kind that the status quo generates directly out of its context and setting, and if it's a good status quo, you should be able to tell a lot of those. The X-Men can go out and save the world a lot without needing to make changes in their setting and context, and it'll probably be exciting.
But "illusion of change vs. real change" translates, here, into "deviation from, and return to the status quo vs. transition from one status quo to another new status quo." An "illusion of change" story is one where something happens to upset the status quo, the setting and context of the characters' lives, and their efforts to return things to said status quo. For example, the X-Men went through a very long "illusion of change" story from Uncanny X-Men #200-280, where Professor X left Earth, the team faked their deaths and moved to Australia, the mansion was destroyed, and several characters lost their memories of being X-Men, all before Professor X finally returned and helped set things to rights. (Which brings up an interesting point: That storyline wasn't well received, because it went on for a very long time and people were frustrated that there seemed to be no end to the changes. You can only deviate from the status quo so long and so far because "meaning" comes from setting and context--without a world to ground the story you're telling, it becomes pointless. Status quos are necessary because they provide that context. But I digress.)
"Real change" stories, on the other hand, change the status quo to an entirely new one. They demolish the old story-generating engine, and create a new one. For example, Batgirl got shot in the back, suffering permanent spinal damage that confined her to a wheelchair, and became the tech-savvy Oracle, leader and mastermind of the female super-hero team, 'The Birds of Prey'. That's a significant and permanent change--you're telling a completely different type of story with Barbara Gordon than you told thirty years ago. You have a different status quo.
So, here's where it all comes together. "Real change" fans think that they're advocating "no status quo", but you can't do that, because a status quo is simply a context and setting to your character's continuing adventures, which is absolutely necessary to give the story its emotional grounding. They're simply advocating that status quos should feel free to change. "Illusion of change" fans recognize the point brought up back near the beginning: Not all status quos are created equal. Not all story-generating engines have the same number of stories in them, nor the same quality. (Notice how 'Buffy the Vampire Slayer' tended to founder a bit after they left high school? New status quo, not as many good stories in it.) Changing to a new status quo is only a good idea if the new status quo has as many or more good stories in it. Otherwise, you're just closing off interesting possibilities. Which means that changing the status quo shouldn't be done lightly or often, especially in comics--a lot of these status quos have managed to keep going for decades because there are so many interesting stories to tell with them; changing the engine could wreck it, and it takes time and effort to fix something like that. (Witness the 'Clone Saga'.)
There ya go. Why status quo is important, why it should be viewed as valuable, and why you shouldn't tinker with it too much when you're writing an open-ended series (like, say, having Scott Summers get mind-controlled by Jean Grey's ghost into falling in love with the White Queen, right before you leave the series.) And all in just a few hundred easy paragraphs.