My first attempt at explicitly saying why the PE spec does not try and also explain how UAs can handle both touch and pointer events. Probably too wordy...feel free to hack it into shape.

This would be an expansion of the last paragraph of the current introduction:



"While Pointer Events are sourced from a variety of input devices, they are not defined as being generated from some other set of device-specific events. While possible and encouraged for compatibility, this spec does not require other device-specific events be supported (e.g. mouse events, touch events, etc.). A user agent could support pointer events without supporting any other device events. For compatibility with content written to mouse-specific events, this specification does provide an optional section describing how to generate compatibility mouse events based on pointer input from devices other than a mouse."



Split up slightly and expanded, I'd propose this (still just as main text for the intro, not as a separately highlighted NOTE or anything).



"While Pointer Events are sourced from a variety of input devices, they are not defined as being generated from some other set of device-specific events. While possible and encouraged for compatibility, this spec does not require other device-specific events be supported (e.g. mouse events, touch events, etc.).

A user agent could support pointer events without supporting any other device events. Conversely, a user agent could support other device-specific events in addition to pointer events.

For compatibility with content written to mouse-specific events, this specification does provide an optional section describing how to generate compatibility mouse events based on pointer input from devices other than a mouse.

This specification does not provide any advice on the expected behavior of user agents that intend to support both pointer events and touch events [link to http://www.w3.org/TR/touch-events/]. Although in the case of touch input there are some superficial similarities between pointer events and touch events, their model - implicit versus explicit capture, the <code>TouchList</code> objects, the way in which compatibility mouse events are fired and suppressed, the fact that touch events consider <code>click</code> to be a compatibility event which can be suppressed - is fundamentally different, meaning that user agents will have to employ complex strategies and decide on which model to prioritise when attempting to handle both event types. [should/can we point to the W3C Touch Events CG here?]"