As a recent convert over to Sonarr from SickBeard, it’s been a fine experience so far but have issues with the Calendar format. It’s fine but I’d prefer a list of episodes that are upcoming or missed much like the Wanted section of the UI.
A different limitation is that Upcoming will only tell you about future airings in the current month so even if something airs next week and you’re in the last week of a month it won’t display anything so it does limit its usefulness.
Final issue for me is with how it displays seasons which are released as one bingable blob, every episode is displayed which means it’s a decent waste of screen space and wonder if multiple episodes air in a given day then it can be reduced to one marker with an episode range (though that would mean displaying the episode numbers too).
Not sure how many have been suggested in the past or if they can even be implemented but can’t know unless I ask, thanks for your time!