* It'd be nice to have some sort of search feature for adding activities (incremental search or otherwise)
* On a similar note: if you don't see the exercise you're looking for on the exercise database, it'd be nice to be able to add the exercise from the same modal.
* it seems like there are a lot of missing workouts for strength. I know it's not easy to find a centralized database for exercise listings, but common things like 'squats' shouldn't be too hard to add in.
Definitely would like to see some sort of FitBit/Withings/Myfitnesspal/LoseIt! integration. It'd also be lovely to have charts documenting progress, and an ability to export to csv.
I think once the mobile apps come, this could be fantastic--I always have my phone at the gym for music, but will occasionally forget to bring a journal for tracking.