I'd really like to see HRV readings with the ECG on the Venue 3 - either exposing HRV in the current ECG app or offering a discreet app that reads and exposes HRV from the ECG ring on the Venue 3. That data is already being collected, so it would only be a matter of exposing it.
Using the ECG for HRV readings would be much more accurate than the Health Snapshot optical estimations, and would replace my need to use a chest strap to take discreet HRV readings in the morning.