I just missed a call and wanted to bring this up again: Just two short vibrations (and a third one for the missed call)! This is ridiculous!
Threads about this shortcoming are all over this place (for almost every device and since many, many years) and Garmin still isn't able or willing to fix this.
I've seen workarounds (Android + Tasker App), petitions and pleas, but Garmin doesn't care.