I think the keyword here is testing. Notice that the title is iPhone 8 will replace Touch ID with face detection, and that the text itself says testing:
Bloomberg reports that Apple is currently testing using 3D facial detection as a replacement for Touch ID fingerprint authentication.
(I added the emphasis.)
Either way, I will for now hope that they won't replace Touch ID because I really love it. It's so fast, works reliably, and is convenient and works everywhere all the time. And most importantly, it doesn't feel awkward to use. It's one of my favorite features with the iPhone 7 (and 6s (and 2017 iPad Pro's.))
I guess facial recognition could work too if it's as polished as Touch ID, and I'm fairly sure Apple wouldn't ship it if it wasn't better.
The article also mentions that ProMotion/120 Hz might be coming to the iPhones, which I don't feel strongly about either way. I have it on my iPad and it isn't that big of a deal - I am still able to use 60 Hz displays (like my phone) without being too annoyed.
It's a more striking difference at first but once you're used to it it's not that big of a deal.