Forgive me if I'm wrong, but those features were later available on the Moto X through
Moto Assist... which they've
discontinued for Marshmallow+ users because:
While I'm familiar with the Moto X models, I haven't personally used them for extended periods of time where I'd be commuting with it and such. If M truly does replicate the contextual features of Assist, then I have no issue with that decision. If M's features are "close enough," but lacking some of the contextual "magic" (specifically the in-car conversational steps as mentioned above), then that's definitely a loss, though I can understand Moto's motivations regardless. It really does come down to the complementation versus competition of features, and when such decisions have to be made there are almost always a few details or nuances that are lost as a result.
I use Bluetooth far less often than most, so I'm not much of an authority there, but that's my two cents on why people may have felt a bit let down as those originally-innovative Moto X features have made their way into Google's code base and Moto doesn't feel the need to maintain their own version any longer.
What don't I like about the 6P?
If there is any moisture on my fingers at all, or significant humidity (i.e. some condensation on the 6P itself), the fingerprint sensor is useless. It's excellent in dry conditions though, fast and accurate, and I didn't even bother to train it "well" on my fingerprints.
It's as large as I would want to go with a phone, and I'm glad it's not any wider than it is -- back when the first phablets were announced, a major observation was "more height can be useful and adaptable to, but more width very quickly becomes a usability problem," and that still holds true. I love the feel of the 6P itself, but because it's at that upper size limit already, adding any type of case or bumper makes me feel like I'm so much more likely to mishandle and drop it that the case isn't doing me many favors.