Having a feature where you can auto generate a report that can be exported to a PDF for clients. This could be over a set period of time or phase.

Giving the trainer the ability to select certain features for the report and to have a custom feedback box at the bottom. This would let clients know how they are getting on each month and give them a better look at the numbers and graphs. It would also save the trainer a lot of time custom building one as a document each month.