I just wanted to report back on my 2016 MBP 13" keyboard. I think I already mentioned that my up arrow key seemed to require a little more force than the other arrow keys. It didn't bother me too much, but earlier today I was making frequent use of my arrow keys and it was driving me crazy. I'd be curious to hear from other 2016 and 2017 MPB owners as to how that key works for them.
As I mentioned before, even though my MacBook is a 2016 model, it was just purchased a few months ago, and I'm pretty sure the issue has been there since day one, so I don't think it's a dust issue, but rather a design issue (I believe there's a thread somewhere about the directional keys on the 2016, but I'm not sure if it was improved on the 2017).