So what is it about the XO that would cause the Scorpio to be unbalanced if you had to support it?
If your saying that you wouldn't be able to make say a hugely expansive open world game that you may have been if you only supported the scorpio, that that's fair enough, but that doesn't make the machine unbalanced.
Edit - Sorry this probably will derail thread. I don't think you can say because PS4P made certain decisions that MS's machine will be doomed architecturaly also?
If they want the Scorpio to be fully compatible with existing X1 games without emulation they'll have to use similar hardware. If they don't want to alienate the current user base some rules must be kept, such as same framerate in multiplayer games between XB1 and Scorpio. We know the Scorpio will have VR exclusive games (all of them) so there's that. We also know that Microsoft are trying to unify the platforms (or at least make the differentiation less transparent) through UWP but we haven't really seen that work yet.
In short, any console "refresh" is limited by the previous hardware because it has to support it natively. Sony went the route of Ps4+ with some clever tricks (that we'll have to evaluate at launch) to achieve 4k, but at the same time kept the gameplay experience between the two systems largely the same. It is yet unclear what Microsoft are trying to do and we'll probably learn more at E3 next year.