I apologise for the length of this response - I have major problems with brevity! In summary, my own inclination is that the current stance City are taking is absolutely the right one.
I think, in general, if you get caught bang to rights or if an investigation starts that you know will uncover incriminating evidence, then it's better to admit it. I personally doubt that we're in that position here. Apart from anything else, if there'd been anything that clearly pointed to our guilt, surely the PL would have laid charges rather than still been plugging away four years on. They'd probably have done so for anything that was borderline, too.
Assuming they've nothing by way of evidence that wasn't printed in Der Spiegel or aired before the CAS panel, then they can doubtless make a case that City have sought to circumvent various regulations in a way that the regulators themselves may not have anticipated. We also probably have a closer relationship with certain Abu Dhabi state companies that some of our critics would deem fair. After all, we were able to contact a couple of them and ask them to increase our sponsorship fee to help us meet an unexpected expense - and they did. You can bet most entities sponsored by Abu Dhabi state-owned companies wouldn't have such a request met with that answer.
If people want to criticise us for that then it's their prerogative, but they should be knowledgeable enough to be aware yet honest enough to admit that none of it means we've broken the rules. Nor is that a borderline call. Every day, all over the world, companies work with legal and financial experts to lawfully avoid the effect of regulatory regimes that have the potential to have a detrimental impact on their business. That IMO is what we've done, no more and no less.
We "took a pinch" once and our executives, though recognising discretion to be the better part of valour, were furious about having to do so. The chairman said we wouldn't take that course again, and I'm inclined to believe that we wouldn't accept a punishment on a second occasion when we think it unjustified.
I suppose I should add that, in any litigation, the specialists will tell you that, even with an incredibly strong case, you're never certain to win - usually, your brief won't venture a forecast of higher than an 80% prospect even if your case seems unassailable. For that reason, the overwhelming majority of cases are settled before they get to court. You can argue, as Stefan for one did, that the prudent course would have been for City to settle the case against UEFA before it reached CAS if they'd suspend or lift any ban.
It worked out OK for City in the end at CAS: in other words, what was probably a calculated gamble paid off. We're not at the stage of deciding whether to run a similar risk with the PL as far as I can tell. We seem to have invited the PL to put up or shut up, and they seem unable as far as I can tell to do the former while remaining unwilling as yet to do the latter. If they ever do charge us, we'll have to see what the accusation is and take it from there.
The only other point I'd add is that City's uncompromising stance may be acting as a deterrent to the PL in trying to put forward a weak charge or two. They know we'll throw everything at fighting any accusation unless they can clearly prove it and I think we've done right to ensure that they understand the point.