The biggest issue with purchasing at launch is that you are basically serving as a guinea pig for the company in question to refine it's product with. You have to suffer through the possibility of unstable hardware, and then have to put up with the on-line services and interface getting built up around your ears. The same thing happened with the 360. (and by extension, the PS3) The eventual state that the 360 reached is far different from where it started out. The interface didn't go through one or two major revisions, but more like seven or eight. Early 360 adopters served as beta testers while Microsoft went about refining the product.
Now, your point still holds water. If you are getting a year's worth of utility out of your system, than it is much easier to justify paying a little extra to have it early. And I think that with the XBox One there is ample reason to think that you could get a year's worth of use out of it. If nothing else, it is now capable of playing Blu Ray discs. And it's other media capabilities could have people using it every day.
I wouldn't compare it to a Harmony remote, though. The interface for the Harmony is considerably more flexible, and in many ways more versatile. The XBox One won't stand up very well in that comparison.