I desperately need a tap down event too.
My usecase: I have a puck that needs to be dragged from a starting position to one of two finishing targets after listening to a sound. I need to simulate the sound and play an animation as soon as the puck is pressed, then the user drags the puck off to make a decision: yes or no.
Imagine something like Tinder but you need to press and hold the card before sliding it to yes or no.
I can put all the events on drag start and teach hallway test participants to do the little drag to start everything but I can't go to usability testing without a genuine tap down event.
...and I really need to go to usability testing with this interaction model.
Please, please may we have a tap down event.