I would love to see combined charts in the report widgets for correlation, e.g. heart rate and speed in the same graph. Obviously combining them yourself would be perfect but preset graphs would suffice.
On the activity page, just above the map, is a series of tabs. You should see a Details, Splits, and a Player tab. Click the Player tab. You can show two data sets on the graph simultaneously.
Can't find these "tabs." I assume you're talking about the single-activity display, right? Above the map I have no tabs, only the edit selections for Event Type, Course & Gear. On the multiple "Activities" page, I see no tabs, either...