It would be great if clients were given a number of “suggested exercises” if they weren't able to do the prescribed exercise in their workout. For example, if a client didn't have access to cables for a cable chest flye, the substitutes would provide alternative exercises for the chest.

It would mean that clients wouldn't need to remember additional names of exercises, and it would save time searching through the entire library for what to substitute in. They could just look, and pick an exercise they feel most familiar with.