I think the iPhone 8 will be the phone to buy if you are getting a new phone anyway.
But, I don't expect it to be anything that compels me to upgrade from my iPhone 5.
iOS is iOS. That's the problem. If you have a phone running iOS already, then you can already do pretty much everything that a new iPhone can do.
For me, the only thing I'm lacking the ability to do, are things I would never do if I could do them.
So, to get users like me, who are content with their current iPhone to upgrade, Apple has to do something that makes me want it or need it.
Everything they've done since the iPhone 5 has been uninspiring too me. I don't like the new thin fragile designs. I don't have any use for ApplePay. I don't care for watches that monitor my body (I'm able to tell what I need to know without an electronic device). They haven't found that feature yet that makes me desire a new phone.
Probably the only feature in the current rumor mill for eventual inclusion that interests me, is wireless charging and full wireless syncing / updating (as in exactly the same as using a cable) and backup through iTunes on my computer. And by that, I mean that actually reliably works every single time. As functional as a data cable.
Or, even just getting rid of the delicate lightning cable and replacing it with something durable. I'm tired of buying new cables all the time. I've never had any other cables jackets wear out so easily.