I also have had problem with not working alarm, which is mostly fixable by rebooting the phone, even if in some unexplained cases it fixed itself without restart.
Second problem is the Battery Saver which don't track battery drain due to Wifi or Data. Which even if some say is due to the API is a big problem, that should be addressed, and if needed - the API reworked..
And finally - I consider the core apps provided by MS as relative to this thread - lice calendar, people etc.
in the calendar app, we are unable to change the reminder type for events or birthdays imported from Facebook. Detailed explanation below:
the events / birthdays imported from Facebook appear, and it automatically puts alerts each day at 12:00 whenever there is someone with a birthday - 1 alert for each person.
Similar with events where I am going or have been invited.- there is an alert 15 minutes before start.
With sound, and notification with snooze / dismiss.
And this is quite annoying. Until now I have not found any way to disable the sound of these reminders, which is the most annoying part.
I just want these events to be visible on my calenar app "for information", but not to get 5 reminders at 12:00 with sound, each day!
For any other events - specifically the ones I have created on Outlook.com's calendar I can choose the type of reminder, or disable it, but hot here!