A report on the beta version as of 19 November. This looks like it was a lot of work, so: thanks!
The authorization scheme seemed to work ok, although it might be good to explicitly suggest pinning the widget until that step is completed (since if the widget rolls off, it starts over with an entirely new auth code, etc.)
I too was momentarily thrilled to see multiple calendar selection... until I saw that the checkboxes were really a one-choice radio button. The old widget required multiple instances for different calendars too, but if there was some way, some day, to select multiple calendars and show the "union" of their events, that'd be a huge plus.
So would being able to select as the default display an even more compact "today's agenda" page -- that'd be more useful than event-editing, in fact. BTW, a minor UI suggestion: for the day view add a short day designator before the date, e.g. "Wed Nov 19th 2014". You could always loose the -th/-rd/-nd/-st if necessary to gain some space.
ANYWAY: it does seem to be talking to my calendars (I have 8 on my selected Google account), but its acquisition of events is flaky. Events are in some cases not seen at all on a given day ("no events"), or sometimes just one of several on a given day is seen and rendered on-screen for that day. In some cases the "missing" event is placed on a different day, days or weeks 'off'. (Maybe ALL the missing events are just misplaced... hard to say!). My primary calendar (native to the Google account, not just subscribed) on first selection showed no events at all for the several weeks surrounding today, and there were actually quite a few. After fiddling with some of the other calendars for a while, with the results noted above, I went back to the primary calendar and this time it showed several events around this week -- but again, in many cases, misplaced or sketchy (some in place, some missing, some misplaced).
I can't see a pattern of problems peculiar to JUST one-off events vs. scheduled events. Interestingly, many of the events that ARE shown at all ARE shown on the correct day, including some that have rather elaborate repeating rules. So it's not totally random... it's CLOSE!
When an event is shown, it does seem to usually have correct detail info... but not always. For example, I had a lunch appointment on Nov 12 from 12:45 to 2:15pm ; it's rendered here from my primary calendar TODAY Nov 19, "All Day". But the title and location info are correct. (Today also accumulated several other misplaced events from the past week or so.)