Noxus was always super Darwinian, complicit in atrocities under the rule of a semi-immortal leader, but characters like Darius, Riven and Swain represented a desire for change. Noxus was too corrupt, ruthless or shortsighted, respectively. Noxus was bad. Not BECAUSE it was bad - but because it had to be for characters to want to effect change from within. And the lore was heading in that direction, for a time.
Now, Noxus is the evil empire. They are unconcerned with internal reform. They're just the war nation. Kled would have been a nice touch if he had been an example of Noxus reluctantly overcoming its discrimination against Yordles. Instead, it turned out Kled has 'always been there'.
Demacia was pretty boring, characterised heavily by its war with Noxus. But the majority of League's lore was written through the perspective of its characters. Garen was a selfless bastion and was rubbing off on Katarina. Lux was traumatised and empty, alluding to the lack of choice people like her truly had to choose the direction of their lives. Jarvan exuded power and resolve; narrating Demacia's noble push to pacify its surrounding regions (being incorruptibly good can be fun if you are, say, wiping out dragons and demons).
It's also worth noting that Swain and J4's rivalry was as gritty and cerebral as League's lore ever got.
Zaun was libertarian capitalism (nothing off-limits, provided you can pay your way).
Piltover was liberal capitalism (regulated capitalism, like in most Western nations).
Zaun was only portrayed 'evil' in the context of characters being hired by Noxus to murder stuff. Some awful stuff was happening in Zaun, but there wasn't really a governing body in the traditional sense. You paid for protection, there. You paid for security. And if you did that, you lived a pretty decent life. After all, there were bright eyed university students (Viktor), wrong-done environmentalists (Janna) and state celebrities (Mundo).
Clearly dystopian. But definitely not the one-dimensional slum where poor people get experimented on, that it is now. And again, like Noxus - it had people on the inside working to redeem, defend or transform the city into something more in tune with their ideals.
Piltover was portrayed as 'good', because it maintained a sense of ethics and focused less on military application. It was commercial goods and advertisement. It was global problems and solutions. Theoretical scientists and charismatic heroes to the community. But phony. Oh so phony.
It only beat Zaun in one scientific contest (which the lore implied was a big deal) and its brightest minds expressed bewilderment at the achievements of their Zaunite contemporaries.
Their city was characterised, for a time, by flamboyant terrorists. The likes of Jinx and the burglar Caitlyn could never catch. These criminals came across as bored, lavishing in attention and the chaos they caused. Piltover glorified people who would always be more interesting than you, the consumer/the viewer. There was a sense of decay and urgency, as people like VIktor and singed brazenly ignored the supposed influence of the Piltovian government. And the government idly allowed it, giving rise to even more celebrity saviours - 'defenders of tomorrow'
Ionia was a victim fighting to retain its freedom. It was characterised by its crippling defeat - both through sheer military force, and chemical attack. Its former leaders were long dead, abandoned or actively negotiating surrender until Karma and Irelia stepped up in to fill the old guard's shoes.
You'll notice a theme, here. Every nation/city state was actively engaging with an ideology shift. This makes sense, considering that justice journals and character lore generally built on the existing story in a linear narrative fashion.
New lore has discarded this effort, focusing mostly on self-contained, static, characteristics or tropes. The unchanging ideal.