As you said, there is not major failings in the new MBP ... but it comes after 2 years wait, in a side event (i.e. not really the big front stage for this "Back to the Mac"), with muddled message. Apple has made bold decisions in this Mac but didn't follow up by giving the impression it was behind it. You get USB-C, yeah, hopefully maybe some third party will do cool stuff, like screens because Apple is not doing those anymore, ... It is also bad timing with the phasing out of the Wifi Router dropped like that as an unremarkable footnote despite being key in cloud feature like "Back to my Mac" or "Time machine". There was a definitive feeling that something was off.
MacRumors all black buying guide, Apple regular lack of comment about its future plan made that feeling even worse.
Twice in a month after that, Apple had had to confirm that they are still committed to the Mac, both to the public and to their own employees ! That's what people are concerned about. Nobody wants to buy into a dying ecosystem and Apple 2016 has done very little for the Mac. We will see how 2017 turns out, but I'm part of the people that prefer to wait until November 2017 to see if Apple is now sliding the MBP into a bi-yearly release cycle to decide if it is time to think about a plan B.
edit: Forgot to mention. I think on its own that the new MBP is a great machine, I'm itching to get one. I'm actually delaying the purchase decision as much as possible for the reason mentioned above.