Ungoliantschilde

Maria would not want to be a part of the Illuminati, because she would see it for what it is and immediately be opposed to the idea. Once they all insisted -which they totally would- she’d have no choice but to stay there and threaten the rest of them with exposure if they were against her involvement. She’d be forced into the position of being the voice of reason, and it would not be enough. The Illuminati group would still go down dark pathways, and Maria Hill would then be a party to those mistakes, no matter how much she tried to argue against each of their bad ideas.

It’s pretty telling that the first thing the illuminati did as a group in the comics was to assemble the Infinity Gauntlet and try to use it. They wanted to will the gems out of existence, which was not gonna work. Predictably, when the first plan did not work, Reed Richards was still wearing the Infinity Gauntlet.

Just putting on that glove was a bad enough idea for Uatu to show up and tell Reed to stop being stupid. And putting on the glove is the first thing the Illuminati did as a team effort. Bad ideas across the board from those guys, and all borne of good intentions.

Maria Hill would not WANT to be a part of those shenanigans. But Maria would know she NEEDS to be there in order to keep them from getting worse.

OK, so this is a follow up question to your last one.

Maria Hill, or some other representative of the baseline human world saving community would need to be included in any future iteration of the Illuminati because everybody else in that group is already a leader of a group of super powered people, or is in charge of using their super powers to monitor super powered problems. SHIELD still has to clean up the messes that get made, and the vast majority of the world is not a Mutant, not Magical, not Atlantean, not Inhuman, and not Genius-Level Smart. The vast majority of the world is just regular folks doing regular things, and they’re the ones that deal with the fallout of the problems caused by the super powers that be.

I am assuming that Maria Hill is still running SHIELD, because I have not been keeping up with the stories for a while now. Either way, SHIELD needs a representative on the council of people who elected themselves in charge of saving the world. Mostly so that that SHIELD representative can tell the collective members of the Illuminati that they don’t get to decide what is and is not in everyone else’s best interests.

The Illuminati did not work because they were not accountable to anyone but themselves, and being accountable to themselves lead to disasters that affected the entirety of existence. Repeatedly.

Like all REALLY bad ideas, the Illuminati was formed by a group of people with very good intentions. The Illuminati storyline is one my favorite ideas from the Bendis era of the Avengers for exactly that reason. It was a bad idea born of really good and noble intentions.