Eye is super strong but it's also the main card that's letting defensive Ionia decks exist at all, I think that they might be a bit hesitant on substantially nerfing it because I don't think they'll want to kill the possibility of those sorts of decks. The stream Rubin did talked about how they got into trouble nerfing cards that essentially let a region do something that they're supposed to do (like nerfing Make it Rain made BW have much worse AOE which is supposed to be one of their strengths) so I think there's a good chance Eye will be untouched. Alternatively I could see them bump it up to 3 mana and buff the stats to compensate, that would prevent it from being fished out by Crescendum which I think is the bigger issue currently. There's effectively 6 copies of her in Zoe Lee and tons of cards to protect them. The grand finals of OLS the Zoe Lee player played Eye on turn 2 into a Roiling Sands, and it was 100% the correct play because they had effectively 2 more copies in hand plus two Twin Disciplines so there was basically 0 chance of it dying anytime soon. Honestly I think that Crescendum needs a rework at some point because it's only ever going to be used for unfair stuff like that, but I doubt they'll commit to a rework of it at such short notice. All the Lee decks are playing 0-1 copies of Will, it's not really an issue IMO. (The Akshan version ran a single copy of Homecoming over Will)
Shurima is strong overall, but at the same time I think a bit of it is people wanting to play new stuff. I think that maybe a card or two could get some changes, maybe Merciless Hunter because Baccai Sandspinner also exists as a source of granting permanent Vulnerable, but at the same time I think it's a really important card to make sure back line units have counterplay as it's otherwise really hard to fight them. (And again this goes back to Disciplines being too strong as it's extremely good at stopping their backline units from being interacted with) Rock Hopper and Shaped Stone are important to make Renekton and the landmark synergy stuff in general work, Treasure Seeker helps out Reputation, Sivir is finally getting her chance to do cool stuff and Ruin Runner is an important tool vs spell or chump blocker heavy decks. I guess maybe you could lower Runner's health a bit to make it weaker vs other creature-based decks. Overall though I think most the cards are only slightly above curve and I think that if you nerfed them it would substantially weaken at least one fairly cool and unique deck which isn't great.
I did a prediction on Reddit before the Shurima expansion guessing what characters would show up in the next cycle. I got 5/7 Shuriman champs right and 1/8 of the non Shuriman champs. (I guessed Targon would get a non-Targon champ though so I was sorta right about that too) The upcoming cycle is going to be borderline impossible to guess both because we don't know what the 10th region will be and that there is rumored to be multi-region cards which might inflate the amount of champs added. That's not going to stop me from throwing out some hot takes though. To help myself a bit, I'm going to guess two champs per established region.
Demacia: Lux hasn't gotten any support at all through the Targon and Shurima cycles in addition to the two champ expansions. I think this is because they plan on adding in another champ who will help her out, so I'm guessing Sylas will join her.(Sylas 2nd region could be FJ) Second champ I'm substantially less confident in. If it isn't Senna as a SI+DEM dual region champion, I'll guess Vayne as a sort of monster hunter champ.
Noxus: This one is really tough, if dual region champs are a thing I could see Cassiopeia or Samira being NX+SHU champs, but I got burned by my favoritism towards Cass last time so I'm not going to pick her. I'm going to lock in Sion as the most likely champ because he's pretty important and I don't think the other 4 champs will get in over him. As a secondary pick I think Kled would be a good choice too as there's some neat things you could do with his gameplay.
Ionia: Ionia is a really tough region to guess for because it has the most champs of any region, so not only is there a lot to choose from but they will have to give away some of them to other regions meaning that I have to anticipate which champs they might choose for that. As a whole I think Master Yi is a pretty safe bet as he's pretty popular and I can't imagine them giving him to another region. Another super popular champ is Jhin, who I could see being added as an IO/P&Z dual region champ.
Freljord: While there's still quite a few champs from this region left, there's really not a ton of fan favorites so I can't really go off that. I think that Olaf is a pretty good pick as I think a more in-depth berserker could be cool to design. Ornn might be awesome too, but I want to go for a 2nd champ that has any chance at being dual-region, so I'll go with Gnar.
Piltover and Zaun: Again this is a tough region with a ton of really popular champs left to pick from. I'll pick Blitzcrank for my first champ because he's one of the faces of League and I think that trying to create his hook in a card game would be really funny. As a second option, Urgot came from Noxus so I could see him as a NX/P&Z champ.
Shadow Isles: I think Senna's a lock as an SI champ, the region desperately needs more champions and she fits in pretty reasonably well. For a second champ, I think it's going to be Yorick as I don't think they'll have 3 SI champs in a row all be tied into the Ruined King stuff. (Morde could work too as a NX/SI champ)
Bilgewater: If there's 2 BW champs this expansion 1 will 100% be not currently associated with Bilgewater as the region really needs more champs to equal the other regions. For actual BW champs it's just between Graves and Illaoi, I guessed last time the BW champ would be Illaoi to tie into the upcoming League RPG that I figured would be out by the end of the expansion cycle. So this time I'm going to say that the champ will be Graves so when it comes out and I'm wrong I'll at least have a game to enjoy.
Targon: Only champ directly related to Targon left is Pantheon. There's a super high chance that they'll get another off-region champ, I think there's a good chance they might get one of the Angels at some point.
Shurima: I correctly guessed that 3 of the 4 Ascended champs would make it in and Xerath would be left out before the expansion came out. This time I'm guessing Xerath will get a slot though. For dual-region champs there's a lot of possibilities. I'm going to guess Cassiopeia even though there's basically no shot because I want to believe.
Finally there's the 10th region. Post is long enough, I don't want to go into detail but I think that Ixtal will be the game's 10th region. So currently the champs that are considered to be part of Ixtal are Qiyana, Neeko, Nidalee, Zyra, Rengar, and Malphite. While Malphite is obviously already a Targon champ (who also desperately needed champs) everyone else I think is extremely likely to get in. Factoring that in, I think that Kha'Zix makes a ton of sense too as he's the big rival of Rengar. Now for champs that Ixtal can pull from other regions. Firstly, Ixtal is a jungle which means that I think that Gnar could make a ton of sense as a champ. Tangentally I could see them cramming some Vastayan champs too in, which would open up Ahri, Nami (I think they might shove her in Targon though), Wukong, Xayah, and Rakan. Ahri in particular is probably the biggest omission in the game currently, and since there's already so many champs that Ionia needs to add I could see her getting thrown here or also in Bilgewater given she's going there for the RPG. Ixtal also has a ton of elemental magic, so I could see champs like Brand or Janna make it here. (I know that Janna's a P&Z champ, they need to find some they can send elsewhere because they also have too many) Lastly, Riot's made a big deal about Qiyana having 9 sisters, so I think it's expected they'll add a new one in at some point. So I think they'll break ground and introduce one of Qiyana's sisters as the first Champ to be revealed for Runeterra first before league. (Akshan is actually not even playable in League yet, so there's a precedent)
So that is 23 champ guesses, with 8 of them being Ixtal champs which might not be the actual 10th region. If Riot follows the pattern of the previous 3 expansions there should be 17 total champs added in, but if dual regions are a thing there might be more/less than that. (If every region gets a dual-region champ there will be 5 more) If I get 7 or more right, I'll declare myself Nostradamus.
