I am glad you brought this up! I did not go into details in the post on how we will be implementing it, but we do intend to have a cap on zones and a set level for bosses.
For example, when the first few water zones comes out, it is intended for lvl 5 . If you just beat the candy factory and head straight there, the fights will be a breeze. Which is fine! But with the scaling we have in mind, the enemies would cap out at lvl 10. This makes em a bit more interesting to fight, but still easier and should give a strong feel of progression.
There will be a test out sometime soon when we feel like we are in a good spot. and would love feedback :)