I started working out without a trainer a few months ago as well as doing rehab for a nasty shoulder tear. Today I see the benefit of targeting precise muscles and muscle groups, unlike other beginners in this thread.

One feature request I'd add to the pipeline is to filter exercises available by Gym. Planet Fitness is ironically super unfriendly to beginners and limited in what they offer. People could add the exercises available at their gym and grow the database. Conversely, this could help beginner home gymmers plan what machines / weights to buy to maximize their routine.