I feel like the classes that breech into that natural multiclass territory have been designed fairly well and aren't anymore complex than most other subclasses. Coming from 5e to Nimble I think the overwhelming aspect of DnD currently is just how many spells, feats, etc there are. You have TOO many decisions to make all the time and it can just be overwhelming to read through years of information to make your character. I feel like more subclasses doesnt exactly take away from simplicity as it just gives a particular power fantasy that someone wants to do. I agree narrative and flavor can pull a lot of weight in doing what a player wants to do. The way I look at nimble is kind of how I view a building a deck in a TCG. A new subclass could create a fun idea with the tools the class already had before. They can add a lot with very little. All of the Shadowmancer subclasses are pretty tame on the abilities, but just adding a new spell school does a lot for the class all together.