How about a Shuriman militia mobilising against the Noxian claimed territories?
What about Zilean messing with the passage of time for Icathia?
What about Aspect Hosts learning and acting on the Darkin recursion?
What about another huge wave of the void?
What about natural disasters shaking up some places?
Lissandra making moves against other regions?
Blessed Isles? Black Mist?
Drowned Ones? Nagakabouros??
I feel like you are neglecting to mention that Demacia is getting a novel. Like, Ionia vs Noxus would be pretty big, but it doesn't mean that other regions aren't also getting love.
Ionia is not even the region with most lore... Sure it has more champions than any other regions, but in term of lore it doesn't have that much.
As to your ideas...
Overall, Noxus vs Ionia didn't overshadow anything. It's just a common misconception because we got a lot of Ionian champs with the last 2 years (both champs and VGUs). But it didn't prevent Freljord to get lore (Ashe comic, new bios, Silence of the Damned), and if you can track some hidden clues you can even find some more interesting stuff. Darkins and Shurima also had their time with WIOS ans TotG (as opposed to Ionia who's only short story is The Dreaming Pool, and even then it is more of a Syndra short story). Ionia has its fair share of lore, but Ionia vs Noxus didn't overshadow anything.
Ionia isn't getting jack shit this year so any of those are entirely possible imo. (Well, no, Zed's comic is going to be a thing, but way later like at the end of the year, so.) And even then, the Noxus vs Ionia Round 2 still probably won't happen for a while.
I agree woth lots of points but remember that this is a smaller attack on Ionia, maybe just a decoy for something bigger? So we will not get that much on it but I still find it worthy of happening because we all want active wars and the timeline to move forward and if its a second attack on Ionia(which also makes sense) Im all here for it!
All of the listed except the Black mist are huge events that need time to be well thought since they affect too much. While the Noxian invasion is just Ionia vs some Noxians on the shores.
Ionia never lose because they have canon ship Wukong/Ahri
