Nope, it's neither broken nor a bad sign for PP. As far as I can tell your power expanded too fast and in the wrong places. That's not the fault of the system, that's the fault of the players. In other words ladies and gents, greed has been your undoing. So instead of having a knee jerk reaction and saying it's broken, I quit, perhaps you should see how you can help rectify the situation, since you did help cause it.
Someone in another thread described your faction a bit like the Roman Empire, it grew too big and couldn't be maintained, so it collapsed. It's pretty much spot on I think.
I'm sorry, but frankly, you're dead wrong. You couldn't be more wrong. This situation is the somewhat forseeable result of design, and the players can't be blamed at all.
The setup was that a thousand(s) of disparate players, with no readily available means of conversation, no hierarchy, were engaged in a democratic system with, in Elite's consistent style, vaguely understood rules (some of which are only even rudimentally available thanks to the hard work of a couple of players), and given the opportunity to make strategic decisions with only a positive, forward agenda. There is no option given to prevent preparation or expansion, short of camping your own conflict zones, and killing your faction-mates. If they only played in open. Even if you knew what the problem was, there was absolutely nothing you could do to stop those that weren't aware there was a problem.
It's like putting a horde of monkeys in a schoolbus, pointed at a wall, with blacked-out windows, and giving each of them a gas pedal, no brakes, and a steering wheel that doesn't work much. Whaddya expect?
It's not the monkeys' fault. It was a setup. Probably not intentional, but a setup nonetheless.
ED made a choice about the design of powerplay, to make the rules somewhat available, but not in detail. They made a choice about the options they gave the players to communicate, and they made a choice about what influences players could have on the direction of the faction. They made choices to incentivise certain actions. I don't blame them insofar as I don't think they deliberately setup PP to be a mess. I hope not. Nevertheless they wrote the rules of the game. People aren't behaving badly. Given the numbers of people playing, one can safely assume people are behaving, on average, exactly how a group of people can be expected to behave given the circumstances. And you can bet your socks that there is precious little difference faction to faction in the behaviour of the players, except insofar as different factions may incentivise different behaviours.
The only reason it happened to Ald first was luck. It's not because the majority of the membership of any of the other factions knew better or had better command structures.
All this being said, if some things are a mess, it's because FD is working like gangbusters putting so much into the game, it seems to me. Powerplay, CQC, new platforms, upcoming planetfalls...thargoids of course

I would like to see a lot of things be different, but I love that they are developing like mad.