I think it´s more astonishing on Mac OS X than on Windows, since FMI is an Apple subsidiary, but why doesn´t FileMaker support the latest system features immediately?
Where is the support for
- full screen mode (really natively). Still in El Capitan a scripted dialogue is made fullscreen too ... (BUG!)
- notifications center (could be hybrid regarding Windows 8 and 10)
- iCloud saving of files and synch, of course OneDrive on the Windows side
- FM Advanced support with runtimes for appstores Mac, Windows and iOS
- integrated support for the most common system apps or free apps, not only Mail, but also contacts, reminders, notes and calendar - get data from these and push data to them
Note, that some of these points are already part of other threads.