As a non-fan of the series I can recognize the importance of the first game. It was pretty revolutionary in its approach to horror and the modernization of a format most prominently used in older games such as 1992's Night Trap. The premise of animatronics trying to murder you was also smart considering fear, or at least disdain towards, animatronics is pretty common, and capitalizing on that alongside Cawthon's unique style of graphics made for a great approach to the game's presentation as a whole.
It's a real shame that it suffered from over-saturation as a result of the not-even-yearly (from what I remember two games were released literally 7 months apart from each other) release schedule. Here's hoping that the VR and Triple A games can breath some new life into a stale franchise.