So, besides what the rumor says about timing, what's the reasoning for thinking that an upgraded Xbox would be a year and a half from now rather than end of this calendar year? Why not do it to go head to head with PSVR this October/November and announce day-one Oculus compatibility along with access to Oculus-exclusive games in addition to whatever multiplatform VR has released or is coming this year? I mean, whatever the timing, it's going to be an expensive product for both MS and consumers looking at the hardware jump at this stage. If you're on a trajectory that cannot possibly get better with the current model, why wait so long to make waves to correct the course of your brand when we're looking at a possibly open-ended generational length thanks to hardware refreshes happening every few years rather than every four to six?
The currently unlikely and hopeful best bet from MS' side would be to introduce a cheaper-to-manufacture slim revision for the low-end ($249-$299), kill production of and sell out of the current model (Kinect port/HDMI-in) for $349, and introduce the high end model ($499) for enthusiasts that works with VR ($599). Waiting until 2017 feels like it won't have any effect on the commanding sales momentum Sony has with PS4, so beating them to their updated console's release seems like the only real way to go. Sure, the costs of manufacture would be much less for MS releasing it next year, but their brand has lost its strength outside of current dedicated owners and you don't turn that around in the current setup through software alone and you don't do it by letting your competitor go first every step of the way.
Personally, I have serious doubts about introducing new hardware this soon for either platform, but if you're going to try to change the situation, you've got to take some serious risks and pay for them upfront in sacrificed profitability.