Well what bout that the people are squandered her sacrifice? She gave up her sanity to save the world and the people don't learn anything from the past. They keep committing the same mistakes over and over, they let villains control an entire city, the government is almost nonexistent and the Wardens look like the only real source of authority with no oversight (that itself is very worrying since Parahumans subconsciously crave for conflict and you don't want people like that holding power).
As I said, I don't think that alone would be enough to spur Skitter to action against them, alone. With that however, along with how they are failing the common people, and prosecuting those that support Skitter, and even refuse to give proper incentives to increase farm and food production due to how it may create an early noble class among the citizens, that would for sure be enough to spur Skitter into action against the Wardens and their puppet government. Not to mention the exiling, the rigged elections, the no oversight. All would give Skitter a very good Casus Belli for invasion and conquest.
Also is better put that the living world operate under different rules then the post-mortem, say demonic magic can work on Earth but is weakened since reality is not easily defied or broken and demonic powers have no place in there but nothing is stopping her from leaving the circle, imps can walk around Earth with no problems there is no reason why she couldn't do the same.
The way I was setting it up was that the reason Taylor is unable to leave the circle has nothing to do with her demonic nature, but rather has to do with the QA wanting to reconnect, but because of incompatible hardware, it results in a broken trigger thus causing death, chaos, and likely killing Taylor, thus her soul returns to Hell and QA is left with a rapidly crumbling demonic body she has no choice but to pilot until it, itself dies and it is left scanning around for Taylor to show back up again to try again.
Also the shield thing is probably above her power, since only Lucifer probably can do it and she probably would get in a lot of problems with Heaven if she try to expand Hell in the living world even if it was a fraction along with the other Overlords since there must be a reason why these powerful demons don't try to conquer Earth. Not considering the fact she would hamper the efforts of Earth Bet evacuation efforts.
I personally don't see it as beyond her power, but then her mortal followers would be doing it. Though I mostly would say it's possible because it is a massive ritual that requires not only the city to be conquered by that point, or having the ritual secretly created, and then a lengthy process of the creation of the ritual where the nodes have to stay intact or else the ritual fails. I don't see the dimensional shielding as anything more than something that can be put into place for a short period of time before it has to be recharged. Thus Skitters direct reign in the Megacity will short but that doesn't mean she can not obtain a host and possess it to continune her reign there.
That or the ritual could drag the city to hell itself and suddenly they have to deal with the legions of the damned that Skitter has loyal to herself.
As for problems in Heaven it might simply be academic or it could be a major thing that opposes Taylor alongside the Wardens. Hell could be that after Skitter's first attempt and summoning is stopped by angels who then impose a dictator or something upon the city.
As for the evacuation, it would be continued. After all, dimensional fuckery can be recreated once the dimensional shield is down, only the portal would have to be made anew, or it could just be magic and set to the same place.
In my headcannon each universe has they own versions of Heaven and Hell, so she try too expand Hell Bet power on Gimel may cause problems with Gimel Hell and Heaven over jurisprudence too.
At the moment I won't comment too much on if there are other Hells or other Heavens as I haven't thought as hard on that question.
Would she be mind fucked though, she was starting recover herself at the end of khepri, And im sure QA would be actively trying to hold itself so as not to break best host.
Due to it being a broken trigger scenario there likely would be more than the usual amount of Mindfuckery going on. I see the connection things as a fire and forget kind of thing where you fire, and it is either a hit or miss. With Taylor, the connection is set and now the process is irreversible. QA however would refine the process with each successive connection as it would have to be trial and error until after it is fully successful. Given enough tries, heck maybe even works on the second try, QA would be able to properly connect and Titanification could possibly commence, if not for the fact that when Taylor leaves the mortal realm the connection is severed and QA would have to start again, or get transported to Hell.
With a host body being possessed on the other hand, there needn't be a problem of connection severing as both Taylor and QA could control the body and make it a Titan with them both in charge.
