It's great that ArcGIS hosted time enabled layers automatically trigger the addition of a time slider in the web map, but it looks like the time display format is hard-coded. My time field has a 4 character year (no month/day), and I have no interest in showing month/day in the time slider, but ArcGIS Online adds it anyways. Please allow us to change the display format.
Also, I would love to see the time slider in the comparison web app, where you can have multiple web maps displayed side by side. It doesn't seem to show up in this app.