I currently have a steel Series 6. The larger, brighter display is the same on both the 7 and 8, which will be very welcome.
Car crash detection will be one of those features I'll be happy to have and hopefully never need, though I will almost always have my upcoming 14 Pro Max with me in the car, so a moot point.
Ovulation analysis... Wrong gender for me to take advantage of! Though if they can get the temperature sensing to be more general in a future watchOS update, I would find that useful as my home is a revolving door of illness with a nursery age son.
With depreciation so bad on Apple Watches, that £130 hike is becoming a bitter pill to swallow as I'll never see that return. Decisions, decisions...