I don't know. I thought it would be a fun idea to see what other people think the next iteration of "levels" would be after 99 or 100. Let me know what you think they might do.
For my own thoughts...
In a story sense,
I personally think it would be cool if they let people become an archon over the course of the second mainline story. I would have the player start out similar to how substitute teacher trains to become a fully qualified teacher. I wouldn't start them out as a student since saving the world is kind of our thing. Not a full class either so the player doesn't have to run back and forth between "new adventure" and Sharlayan. Just be mentor to maybe one or a few that have the ability to tag along on your adventures. That can -act- as a stand in for the twins if they do their own thing but isn't solely just a stand in character(s) that would be able to react to player choices.
In a mechanical sense,
I think it's kind of hard to consider this since it's become obvious they are moving away from variation with in jobs and roles even that make things like skill trees or something akin to the cross class system just will not happen. (I could be wrong though) I think from that aspect and using the same idea, I think it would be better to make levels functionally the same but instead of calling them levels, it's just ranks of study. In this, I would also have the "xp" gain be determined by the student(s) you mentor rather than the player. To add further to this, I would say that, for example, currently we go from 80 to 90 right? Each part of the MSQ is determined by individual levels like 81,83,84,87 as well. I would give the player the new "rank" only at the end of the level cap for the expansion. That way it doesn't seem like the player can say "you should wash your hands to prevent germs" and get a rank like it's some big achievement. Individual levels would be, like I said, functionally the same but are called like "mentor progress" or something.
I also kind of like this idea because I think at the end of the next 10 year story is when you finally become an archon in name and you can like end the game on that last footnote. Granted, this is my idea because I think it would be cool but not everyone may want to be one. We could just start using a certain special crystal to determine "levels" but is explained as mastery over dynamis.
Just as well, I'm not like some expert on story or mechanics so who knows if what I'm saying is even reasonable. What do you think they will do?