I haven't read it all, but the PL has backed itself into a very dangerous corner in my opinion. Bearing in mind that City are now just part of a huge football organisation with almost limitless backing that on it's own makes the PL look like a Sunday League committee, what exactly are they going to prove?
This is a case of slinging enough crap to hope that some of it sticks. I'm damned sure that City are not going to offer them any potentially incriminating documents, so all that leaves them with is "failing to co-operate in accordance with the rules".
That on it's own isn't the greatest ever crime, and they can't do an awful lot with that except give us a large fine, possible transfer embargo, and points deduction. The EFL doesn't particularly want us because that means someone else will have to miss out, probably through losing a promotion place for the season, and EFL clubs probably won't either because it means we'll be odds on for promotion - nobody will want to play us even if half the squad leave, and nobody will want to finish a place lower than they otherwise would have - especially if that place is the top spot.
If they want to hit us hard then it might be something like a 60-point deduction next (or whichever) season, meaning we would have a real fight to stay up and avoid natural relegation, but that would likely be considered excessive for what was technically a minor misdemeanour.
They also don't want to put themselves in a position where the club might be in real trouble and put hundreds of jobs at risk. They can't be seen as the big bad wolf at the end of it. And if they come down too hard, there might be a few other clubs who start looking over their shoulder. They can't be seen to be trying to destroy the club, and they have already shown themselves in a bad light in the opinion of many professional football and legal people for taking it this far - don't read too much into the media hysteria and the opinion of other fans, they are just along for the ride.
This is a long shot, but if, for example, they wanted to put City in the 2nd division then the EU Super League then starts to look very tempting. And if the likes of Barca, RM and co get it together, others WILL follow regardless of what the fans think. Most major clubs now get the majority of their revenue from commercial operations, and half the fans at the top clubs are "tourist" fans now. They're the ones with the money, and that's what it's all about at the end of the day. People like Boehly - as bent as they come (how do you win a copyright court case against Land Rover for the blatant copy of their Defender vehicle when you're odds-on to lose it?) - will go where the money goes and if that means to the ESL then that's where they'll go, with the rags and everybody else creeping behind. You think Chelsea v Brentford, United v Bournemouth, City v Barcelona etc. every week makes good reading for them? Neither will they, and neither will the PL because their very existence will depend on it not happening.
Guilty or not, there's only so much the PL can do. And it's not much in the greater scheme of things. Now lets go and really piss them all off by winning the title again.