"shows either the presenter notes or the current and next slide"
That is certainly a great bonus for some people in some circumstances. But other people or other circumstances may require a simple remote control, which is lighter, smaller and easier to hold. Just remember how Steve used to give presentations or Tim or the Apple executives give presentations. They use a small remote, not a larger and heavier device like the iPod touch, iPhone or iPad.
In summary, what we ask Apple is to allow third parties to develop remote controls for the iOS devices, so that Apple iOS customers have choices. Everybody wins!