In SP the level cap is always 3 higher than the highest level module (because that's when you stop earning XP). EttSC raised the level cap to 24, and it's stayed there through the releases of CoC, AI, and now CM. Which isn't surprising, because level 25 is when chars get their first Great power token (). But now @Jon and @Flaxative need to decide if we're going to stop here and just add to the middle of the campaign (we still don't have any level 15 treasure hunts), or if it's time to push into the great unknown. Obviously a new token will need extra care in balancing, and if we want people to be able to use multiple Great items on a char, we'll have to go even higher than level 22. Also, 3-card items don't need until level 27, while 6-card items need starting at level 22.5. So what if we had a double sized expansion with 12 modules (two each for levels 22-27)? That would raise the level cap to 30, where chars will have . Assuming items in the same range as the adventures, we'll have at least some 3-card items needing and also some 6-card items needing . Of course, none of this will affect PvP unless we change that to level 27, which would require modifying all the premade decks (the playerbase isn't big enough to support 2 types of Ranked matches).
I'm not sure if the Great power token issue is set in stone, devs already altered the way power token distribution worked across levels in the past to give earlier access to Minor power tokens. You now get a Minor token at levels 5 and 7 as opposed to 7 and 8 (or something like that), so there's no reason to assume they can't change the level up chart again. If for example they change it to give out additional Minor tokens and token upgrades from level 25 onwards it'd take until level 30 to get 12 Major power tokens. There is an obvious problem with this too though, since it'd make the use of tokenless and minor token items mostly unnecessary and also means something has to be done with high-level items that'd otherwise cost Great tokens. They could introduce triple-token 6-card items and double-token 3-card items and increase the max number of equippable tokens beyond the current 12. That way high-level items can still be used in PvP. Either way it seems like there'd be a ton of design and balance considerations that need to be made and questions such as raising the PvP level which is a whole can of worms in and of itself. Personally I'm fine with the current system of level 21 being the highest level a module can be with expansions varying in their level pools. I personally liked AotA's concept of having both low-level and high-level modules meaning you get to use both tokenless, minor and major items for the expansion. I'm a bit mixed on the actual execution since it felt like the two sets were very disjointed, but they don't need to be like that, the base campaign already does the concept well with the three tiers of Demon Portals and goblin stages. This approach prevents the feeling of sets of items being useless such as major token items werre in AI. I also am a fan of expanding the horizontal scope of what's possible rather than just the vertical. I'd be excited to see what else the devs can do with premade content like AI/MM, modular design like CoC and the woefully underused concept of PvE Quick Draw which is already implemented in that one EttSC module. These features could even be tacked on to currently existing modules, in the form of new quests. Heck, expanding upon current modules in general is something I'd like to see. New quest types such as QDing the module, Hard Mode versions of currently easy modules, perhaps something with premade decks against the module or even something like the GM reversal idea I've seen people toss around where you play (altered) monsters against a premade set of adventurers tuned to your characters.
