Seems a little awkward to hit Q and then select in the middle of combat. Hotkeying to numpad seems to make more sense.

Please delete if this breaks NDA

There are video's showing this actually.

Drawing conclusions from that, you pre-assign your Q, you have a round menu from which you select what your Q will be, once selected it is used the next time you press Q.

Again, plenty of reviews video's show it in action, they dont talk about it, but it's visible as daylight.

Seems so much easier to set num 1 to health potion, num 2 to stamina, num 3 to magic. Would have to only use the same potion (health usually) nearly everytime or you are selecting from that menu in the middle of a fight (and by definition the harriest part of the fight)