I have been looking to see what the Fenix 8 will offer for about a year now. I haven't heard anything that sounds like a worthy upgrade. I mean they need something big to compete and pull ahead of the pack. A better HR sensor? I already wear the Chest HR Pro during exercise. The wrist HR has always been goofy. So you have to buy their chest strap to get an accurate reading. And, I am not in the best shape but I'm not too bad either. My 7X always tells me to rest. I would never get any exercise if I listened to the watch.
What they will need, imo
1) InReach capability
2) Heart health monitoring
3) Metrics that are accurate