I would agree with all your points, especially with regard to the flexibility in handling blade variations. The X-stroke would be advantageous in many of the circumstances that you mention, and worthy of mastery. But as you point out, ceteris parabis (all things being equal), a three-inch wide, properly lapped hone will do a fine job without using a single X-stroke.
On the first comment I would respecfully request some clarification. A wide enough finisher works beautifully with a 30 degree angled heel forward stroke. I am not sure what, if any, advantage the X-stroke necessarily provides on a finishing stone. Did you mean to say on a narrow finisher (<2.5in)? Perhaps you can explain this point to me.