For me, a few basic improvements to the Garmin Connect website would go a long way in analyzing data. I have a Vivosmart activity tracker, and use it with the Garmin Chest Strap HRM during workouts.
1) When looking at the heart rate graph, having the heart rate "Zones" on the graph in addition to the actual heart rate value would be nice. You could then visually see when you were in each zone during the workout
2) Aggregating the time spent in each zone would be nice. You could assess your workout by how much total time you spent in each heart rate zone.
3) Options to include things like heart rate or calories for Activities on the widgets instead of just distance. I don't run. I do cross fit and circuit type workouts. Distance is pretty much useless because i'm in my garage the whole time.
4) A 24-hour graph or chart for the day that displays steps, calories and active minutes throughout the day. You could quickly assess when you were active that day, and when you were sedentary. And I'm talking an improved, full-page graph, not the little tabbed column chart that displays your steps for the day.
5) Perhaps some custom or configurable charts/graphs that allow you to access the data in different ways.
I love the Vivosmart, and think it's among the best activity trackers available on the market, but the software lags behind other brands. All the data is there. In my opinion, The Garmin Connect App and and Garmin Connect Website need a few improvements to how the data is displayed.
Who's with me?!?!?