Ionia is, far and away, the most interesting continent/area in lore now.

I'm dead serious and my favorite region is Piltover.

Ionia has become the most fascinating region right under our noses. We see the strife of war wrought upon an otherwise peaceful nation. The noxus-ionia war was a powderkeg that allowed individuals who had grown unhappy with Ionia's stagnation to rise. Not only that but every champion is now affected by this conflict in some way or another. The radical, changing ideals of the world has both people openly embracing it (Zed, Akali), trying to encorporate it into Ionia's mantra (Karma) or those who are so devastated and are unsure about where to go (Shen, Yi)

In addition, most of Ionia's lore progression ties back to the old lore. It's not a 100% total retcon, it feels like the organic growth of these characters. Akali leaving Shen due to his indecision and Shen grappling with the world changing around him. Zed's "haha fuck order" isn't just detesting the old ways but his sense of justice being shaken by a questionable decision made by his master and brother. Karma being torn between her past lives staunch tradition and her current avatar's personal view on Ionia. (Although Karma needed a tweak) And I'm not even getting into the race-relations with the vastaya, Riven's story or Yasuo's mentorship with Taliyah to atone for what happened in the lore.

Kudos Riot. Out of all the regions Ionia is likely the most well-developed and interesting zone you've ever tackled. Well done.