Hmmm, part of me would like it to be a new console, because more power and a good way for MS to start anew. But a greater part of me thinks that would just backfire. Developers haven't even had time to come out with a lot of real XB1 titles yet (e.g., lame load screens in Fallout 4) so the XB1 hasn't reached full potential. On top of which, after XB2 releases, it will take another, what, 3-4 years before we get full XB2 games that take full advantage of the hardware?
And how many people are going to really spend another $400 on a console after having just spent $300-350 in the past couple of years? Your hardcore gamers, maybe. But your typical soccer mom is not buying little Johnny another console for Christmas after having just bought one last year. There needs to be a good, compelling reason to upgrade. 4K is not it. Neither is VR, in my opinion (I know a lot of people will disagree, but I think for the next 5-10 years, it will be a niche market).